Revert github actions change

Author: akshaynexus

.github/workflows/ci-master.yml

@@ -11,7 +11,7 @@ env:
 jobs:
   create-source-distribution:
     name: Create Source Distribution
-    runs-on: self-hosted
+    runs-on: ubuntu-18.04
     env:
       ARTIFACT_DIR: source
     steps:
@@ -42,7 +42,7 @@ jobs:
   build-linux:
     name: Build for Linux
     needs: create-source-distribution
-    runs-on: self-hosted
+    runs-on: ubuntu-18.04
     env:
       ARTIFACT_DIR: linux-binaries
       TEST_LOG_ARTIFACT_DIR: test-logs
@@ -80,7 +80,7 @@ jobs:
   build-windows:
     name: Build for Windows
     needs: create-source-distribution
-    runs-on: self-hosted
+    runs-on: ubuntu-18.04
     env:
       ARTIFACT_DIR: windows-binaries
     steps: