GHA: Run tests on 1.6.x-maint as well

.github/workflows/build-install.yaml

@@ -2,7 +2,7 @@ name: 'build and installation tests'
 
 on:
   pull_request:
-    branches: ['master']
+    branches: ['master', '1.6.x-maint']
     paths-ignore:
       - 'AUTHORS'
       - 'COPYING'

.github/workflows/codeql.yml

@@ -2,9 +2,9 @@ name: "CodeQL"
 
 on:
   push:
-    branches: [ "master" ]
+    branches: [ "master", "1.6.x-maint" ]
   pull_request:
-    branches: [ "master" ]
+    branches: [ "master", "1.6.x-maint" ]
   schedule:
     - cron: "13 12 * * 6"
 

.github/workflows/linters.yaml

@@ -2,7 +2,7 @@ name: 'linters'
 
 on:
   pull_request:
-    branches: ['master']
+    branches: ['master', '1.6.x-maint']
     paths:
       - '.github/**'
       - '**.py'

.github/workflows/tests.yaml

@@ -2,7 +2,7 @@ name: 'tests'
 
 on:
   pull_request:
-    branches: ['master']
+    branches: ['master', '1.6.x-maint']
     paths:
       - '.github/**'
       - '**.py'