chore(java): rename master branch to main (#1221)

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
  image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
- digest: sha256:52b5557b7155a80e6f1684c2376d5eef0df6d8d5c785551e1ff8cc000603b62a
+ digest: sha256:5ba0bc6649b2d147f7dea0836e5b484afba15e10db96e0e5bf01d4edf095041e

.github/blunderbuss.yml

@@ -1,5 +1,5 @@
 # Configuration for the Blunderbuss GitHub app. For more info see
-# https://github.com/googleapis/repo-automation-bots/tree/master/packages/blunderbuss
+# https://github.com/googleapis/repo-automation-bots/tree/main/packages/blunderbuss
 assign_prs_by:
 - labels:
  - samples

.github/workflows/ci.yaml

@@ -1,7 +1,7 @@
 on:
  push:
  branches:
- - master
+ - main
  pull_request:
 name: ci
 jobs:

README.md

@@ -186,10 +186,10 @@ Java is a registered trademark of Oracle and/or its affiliates.
 [developer-console]: https://console.developers.google.com/
 [create-project]: https://cloud.google.com/resource-manager/docs/creating-managing-projects
 [cloud-sdk]: https://cloud.google.com/sdk/
-[troubleshooting]: https://github.com/googleapis/google-cloud-common/blob/master/troubleshooting/readme.md#troubleshooting
-[contributing]: https://github.com/googleapis/java-binary-authorization/blob/master/CONTRIBUTING.md
-[code-of-conduct]: https://github.com/googleapis/java-binary-authorization/blob/master/CODE_OF_CONDUCT.md#contributor-code-of-conduct
-[license]: https://github.com/googleapis/java-binary-authorization/blob/master/LICENSE
+[troubleshooting]: https://github.com/googleapis/google-cloud-common/blob/main/troubleshooting/readme.md#troubleshooting
+[contributing]: https://github.com/googleapis/java-binary-authorization/blob/main/CONTRIBUTING.md
+[code-of-conduct]: https://github.com/googleapis/java-binary-authorization/blob/main/CODE_OF_CONDUCT.md#contributor-code-of-conduct
+[license]: https://github.com/googleapis/java-binary-authorization/blob/main/LICENSE
 [enable-billing]: https://cloud.google.com/apis/docs/getting-started#enabling_billing
 [enable-api]: https://console.cloud.google.com/flows/enableapi?apiid=binary-authorization.googleapis.com
 [libraries-bom]: https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google-Cloud-Platform-Libraries-BOM