build: update to support BETA releases

See discussion: https://github.com/orgs/AlaskaAirlines/discussions/556

1. Branch protection settings are standardized and reused across main and beta branches.
2. A new beta branch is added with the same protection rules as main.
3. Workflows are updated to trigger releases on pushes to both main and beta.
4. The release configuration in package.json includes beta as a prerelease branch,
   allowing for pre-release versions to be handled separately from the main release.

Changes to be committed:
modified:   .github/settings.yml
modified:   .github/workflows/testPublish.yml
modified:   package.json

.github/settings.yml

@@ -49,7 +49,7 @@ teams:
     permission: push
 
 branches:
-  - name: main
+  - &default_protection
     # https://developer.github.com/v3/repos/branches/#update-branch-protection
     # Branch Protection settings. Set to null to disable
     protection:
@@ -70,11 +70,19 @@ branches:
         # Required. Require branches to be up to date before merging.
         strict: true
         # Required. The list of status checks to require in order to merge into this branch
-        contexts: ["test (18.x)", "license/cla"]
+        contexts: ["test (18.x)", "test (20.x)", "license/cla"]
       # Required. Enforce all configured restrictions for administrators. Set to true to enforce required status checks for repository administrators. Set to null to disable.
       enforce_admins: false
       # Required. Restrict who can push to this branch. Team and user restrictions are only available for organization-owned repositories. Set to null to disable.
       restrictions: null
+      # Prevent merge commits from being pushed to matching branches
+      required_linear_history: true
+
+  - name: main
+    <<: *default_protection
+
+  - name: beta
+    <<: *default_protection
 
 # Labels: define labels for Issues and Pull Requests
 labels:

.github/workflows/testPublish.yml

@@ -29,7 +29,7 @@ jobs:
 
   release:
     # Only release on push to main
-    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main' || 'refs/heads/beta'
     runs-on: ubuntu-latest
     needs: test
     steps:

package.json

@@ -96,7 +96,13 @@
   },
   "release": {
     "branches": [
-      "main"
+      {
+        "name": "main"
+      },
+      {
+        "name": "beta",
+        "prerelease": true
+      }
     ],
     "plugins": [
       "@semantic-release/commit-analyzer",