ci: build only on master branch

Restrict push/pull_request triggers to master in build-matrix and
unit-tests, and drop the main-branch condition in the matrix bundle
step, now that the repo consolidates on a single master branch.

Author: amrikarisma

.github/workflows/build-matrix.yaml

@@ -2,7 +2,9 @@ name: Firmware Matrix Build
 
 on:
   push:
+    branches: [master]
   pull_request:
+    branches: [master]
   workflow_dispatch:
 
 jobs:
@@ -63,7 +65,7 @@ jobs:
           if [ "${{github.event_name}}" = "schedule" ]; then
             echo "release_date=$(date +'%Y-%m-%d')" >> $GITHUB_ENV
           fi
-          if [ "${{github.event_name}}" == "push" -o "${{github.event_name}}" == "schedule" -o "${{github.event_name}}" == "workflow_dispatch" ] && [ "${{github.ref}}" == "refs/heads/master" -o "${{github.ref}}" == "refs/heads/main" ]; then
+          if [ "${{github.event_name}}" == "push" -o "${{github.event_name}}" == "schedule" -o "${{github.event_name}}" == "workflow_dispatch" ] && [ "${{github.ref}}" == "refs/heads/master" ]; then
             echo 'extra_makefile_targets=build_both_bundles' >> $GITHUB_OUTPUT
             # uncomment this line for upload! echo 'upload=ftp_upload_bundles' >> $GITHUB_OUTPUT
             # not pushing from matrix

.github/workflows/unit-tests.yaml

@@ -4,6 +4,7 @@ on:
   schedule:
     - cron: '0 1 * * *'
   push:
+    branches: [master]
   #  pull_request:
   workflow_dispatch: