update service resource spec url (knative#2031)

invalid since v0.8.1 (knative#1947)

* invalid since v0.8.1

fix for knative#1859

* remove references to the invalid topic

Fix broken links in API Spec (knative#1800)

RevisionSpec and RevisionMetadata links were broken.

remove cert-manager from serving install (knative#1692)

* remove cert-manager from serving install

* add dynamic version

* remove mention of auto tls

Clarify "event sources" NOT "Knative eventing sources" (knative#1535)

* clarify eventing resources (not just sources)

* Update docs/eventing/debugging/README.md

Co-Authored-By: Sam O'Dell <[email protected]>

api docs gen for v0.6.0 (knative#1349)

API docs for v0.5.0 release (knative#1142)

build version of API docs for 0.4 (knative#1040)

add v0.1 release branch (knative#821)

* add v0.1 release branch 

and provide some indication that the website is coming

* Update doc-releases.md

Co-Authored-By: RichieEscarez <[email protected]>

* temporarily move the TBD link to the bottom

Fix syntax of Knative install command (knative#736)