[CI] Run on all MRs and on release branch (#173)

<!-- [x] Does not require a CHANGELOG entry -->

I know that we are not supposed to have "release" branches, but de-facto
we have them for quick patch releases.

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: fellowship-merge-bot[bot] <151052383+fellowship-merge-bot[bot]@users.noreply.github.com>

Author: ggwpez

.github/workflows/check-migrations.yml

@@ -2,9 +2,8 @@ name: Check Migrations
 
 on:
   push:
-    branches: ["main"]
+    branches: ["main", "release-*"]
   pull_request:
-    branches: ["main"]
   workflow_dispatch:
 
 # Cancel a currently running workflow from the same PR, branch or tag when a new workflow is

.github/workflows/clippy.yml

@@ -2,9 +2,8 @@ name: "Clippy"
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "main", "release-*" ]
   pull_request:
-    branches: [ "main" ]
   workflow_dispatch:
 
 jobs:

.github/workflows/fmt.yml

@@ -2,9 +2,8 @@ name: "Rustfmt (check)"
 
 on:
   push:
-    branches: [ "main" ]
+    branches: ["main", "release-*"]
   pull_request:
-    branches: [ "main" ]
   workflow_dispatch:
 
 jobs:

.github/workflows/test.yml

@@ -2,9 +2,8 @@ name: "Test all features"
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "main", "release-*" ]
   pull_request:
-    branches: [ "main" ]
   workflow_dispatch:
 
 jobs: