chore: reduce ci usage

This should help reduce the CI usage by:

1. Only running  CI on either:

   - PRs targetting `master`
   - pushes to `master`

   Most importantly, CI is no longer doubled in PRs (as previously,
   `push` and `pull_request` would _both_ be triggered).

2. Cancelling existing runs if a new commit is added

Signed-off-by: JP-Ellis <[email protected]>

.github/workflows/build-ffi.yml

@@ -1,6 +1,16 @@
 name: Pact-Rust FFI Build
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: true
 
 jobs:
   build:

.github/workflows/build.yml

@@ -1,6 +1,16 @@
 name: Pact-Rust Build
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: true
 
 jobs:
   build:
@@ -55,4 +65,3 @@ jobs:
       - uses: actions/checkout@v3
       - run: cargo check --no-default-features
         working-directory: rust
-

.github/workflows/compatability-suite.yml

@@ -1,6 +1,16 @@
 name: Pact-Rust Compatibility Suite
 
-on: [push, pull_request]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
+  cancel-in-progress: true
 
 env:
   pact_do_not_track: true