Run GitHub Actions on pushes and PRs to main, not master (#1883)

* Run GitHub Actions on pushes and PRs to main, not master

* fix go install ecr-login, bump to latest v0.6.0

* master -> main in some integration tests

* skip no-ref integration test

.github/workflows/images.yaml

@@ -2,9 +2,9 @@ name: Build images
 
 on:
   pull_request:
-    branches: ['master']
+    branches: ['main']
   push:
-    branches: ['master']
+    branches: ['main']
     tags: ['v[0-9]+.[0-9]+.[0-9]+*']
 
 jobs:

.github/workflows/integration-tests.yaml

@@ -2,9 +2,9 @@ name: Integration tests
 
 on:
   push:
-    branches: ['master']
+    branches: ['main']
   pull_request:
-    branches: ['master']
+    branches: ['main']
 
 jobs:
   tests:

.github/workflows/scorecards-analysis.yml

@@ -6,7 +6,7 @@ on:
     # Weekly on Saturdays.
     - cron: '30 1 * * 6'
   push:
-    branches: [ main, master ]
+    branches: ['main']
 
 # Declare default permissions as read only.
 permissions: read-all

.github/workflows/unit-tests.yaml

@@ -2,9 +2,9 @@ name: Unit tests
 
 on:
   push:
-    branches: ['master']
+    branches: ['main']
   pull_request:
-    branches: ['master']
+    branches: ['main']
 
 jobs:
   tests: