chore(deps): update dependency google-cloud-pubsub to v2.3.0 (GoogleCloudPlatform#5347)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [google-cloud-pubsub](https://togithub.com/googleapis/python-pubsub) | `==2.2.0` -> `==2.3.0` | [![age](https://badges.renovateapi.com/packages/pypi/google-cloud-pubsub/2.3.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/pypi/google-cloud-pubsub/2.3.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/pypi/google-cloud-pubsub/2.3.0/compatibility-slim/2.2.0)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/pypi/google-cloud-pubsub/2.3.0/confidence-slim/2.2.0)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>googleapis/python-pubsub</summary>

### [`v2.3.0`](https://togithub.com/googleapis/python-pubsub/blob/master/CHANGELOG.md#&#8203;230-httpswwwgithubcomgoogleapispython-pubsubcomparev220v230-2021-02-08)

[Compare Source](https://togithub.com/googleapis/python-pubsub/compare/v2.2.0...v2.3.0)

##### Features

-   surface SchemaServiceClient in google.cloud.pubsub ([#&GoogleCloudPlatform#8203;281](https://www.github.com/googleapis/python-pubsub/issues/281)) ([8751bcc](https://www.github.com/googleapis/python-pubsub/commit/8751bcc5eb782df55769b48253629a3bde3d4661))

##### Bug Fixes

-   client version missing from the user agent header ([#&GoogleCloudPlatform#8203;275](https://www.github.com/googleapis/python-pubsub/issues/275)) ([b112f4f](https://www.github.com/googleapis/python-pubsub/commit/b112f4fcbf6f2bce8dcf37871bdc540b11f54fe3))
-   Don't open the google.cloud package by adding pubsub.py ([#&GoogleCloudPlatform#8203;269](https://www.github.com/googleapis/python-pubsub/issues/269)) ([542d79d](https://www.github.com/googleapis/python-pubsub/commit/542d79d7c5fb7403016150ba477485756cd4097b))
-   flaky samples tests ([#&GoogleCloudPlatform#8203;263](https://www.github.com/googleapis/python-pubsub/issues/263)) ([3d6a29d](https://www.github.com/googleapis/python-pubsub/commit/3d6a29de07cc09be663c90a3333f4cd33633994f))
-   Modify synth.py to update grpc transport options ([#&GoogleCloudPlatform#8203;266](https://www.github.com/googleapis/python-pubsub/issues/266)) ([41dcd30](https://www.github.com/googleapis/python-pubsub/commit/41dcd30636168f3dd1248f1d99170d531fc9bcb8))
-   pass anonymous credentials for emulator ([#&GoogleCloudPlatform#8203;250](https://www.github.com/googleapis/python-pubsub/issues/250)) ([8eed8e1](https://www.github.com/googleapis/python-pubsub/commit/8eed8e16019510dc8b20fb6b009d61a7ac532d26))
-   remove grpc send/recieve limits ([#&GoogleCloudPlatform#8203;259](https://www.github.com/googleapis/python-pubsub/issues/259)) ([fd2840c](https://www.github.com/googleapis/python-pubsub/commit/fd2840c10f92b03da7f4b40ac69c602220757c0a))

</details>

---

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appengine/flexible/pubsub/requirements.txt

@@ -1,3 +1,3 @@
 Flask==1.1.2
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 gunicorn==20.0.4

appengine/standard_python3/pubsub/requirements.txt

@@ -1,4 +1,4 @@
 Flask==1.1.2
 google-api-python-client==1.12.8
 google-auth==1.24.0
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0

functions/ocr/app/requirements.txt

@@ -1,4 +1,4 @@
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 google-cloud-storage==1.35.0
 google-cloud-translate==3.0.2
 google-cloud-vision==2.1.0

functions/pubsub/requirements.txt

@@ -1 +1 @@
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0

functions/tips/requirements.txt

@@ -1,5 +1,5 @@
 google-cloud-error-reporting==1.1.0
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 python-dateutil==2.8.1
 requests==2.25.1
 xmltodict==0.12.0

healthcare/api-client/v1/dicom/requirements.txt

@@ -1,5 +1,5 @@
 google-api-python-client==1.12.8
 google-auth-httplib2==0.0.4
 google-auth==1.24.0
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 requests==2.25.1

iot/api-client/end_to_end_example/requirements.txt

@@ -2,6 +2,6 @@ cryptography==3.4.1
 google-api-python-client==1.12.8
 google-auth-httplib2==0.0.4
 google-auth==1.24.0
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 pyjwt==2.0.1
 paho-mqtt==1.5.1

iot/api-client/gcs_file_to_device/requirements.txt

@@ -2,7 +2,7 @@ google-api-python-client==1.12.8
 google-auth==1.24.0
 google-auth-httplib2==0.0.4
 google-cloud-iot==2.0.1
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 google-cloud-storage==1.35.0
 cryptography==3.4.1
 paho-mqtt==1.5.1

iot/api-client/http_example/requirements.txt

@@ -3,6 +3,6 @@ google-api-python-client==1.12.8
 google-auth-httplib2==0.0.4
 google-auth==1.24.0
 google-cloud-iot==2.0.1
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 pyjwt==2.0.1
 requests==2.25.1

iot/api-client/mqtt_example/requirements.txt

@@ -2,7 +2,7 @@ cryptography==3.4.1
 google-api-python-client==1.12.8
 google-auth-httplib2==0.0.4
 google-auth==1.24.0
-google-cloud-pubsub==2.2.0
+google-cloud-pubsub==2.3.0
 google-cloud-iot==2.0.1
 grpc-google-iam-v1==0.12.3
 pyjwt==2.0.1