Use main as default branch

Author: davebarnwell

.github/workflows/ci.yml

@@ -2,7 +2,7 @@ name: CI
 
 on:
   push:
-    branches: ["main", "master"]
+    branches: ["main"]
   pull_request:
 
 jobs:

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
   release:
     if: >
       github.event.pull_request.merged == true &&
-      (github.event.pull_request.base.ref == 'main' || github.event.pull_request.base.ref == 'master')
+      github.event.pull_request.base.ref == 'main'
     runs-on: ubuntu-latest
 
     steps:

README.md

@@ -201,7 +201,7 @@ The repository ships with:
 - PHPStan static analysis
 - PHP-CS-Fixer formatting checks
 - GitHub Actions CI for pull requests and pushes
-- Automatic `vYY.MM.DD.n` CalVer tags and GitHub releases for merged PRs to `main`/`master`
+- Automatic `vYY.MM.DD.n` CalVer tags and GitHub releases for merged PRs to `main`
 
 ## Contributing