Improve CI trigger and concurrency

.github/workflows/cmake-lint.yml

@@ -1,9 +1,23 @@
 name: "CMake Lint"
 
 on:
+  # always run on main branch
   push:
+    branches: [ main ]
     paths-ignore:
       - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'LICENSE'
+  # run on PR to main branch if relevant files changed
+  pull_request:
+    branches: [ main ]
+    paths:
+      - '**/CMakeLists.txt'
+      - '.github/workflows/cmake-lint.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   lint:

.github/workflows/cpp-build.yml

@@ -1,9 +1,27 @@
 name: "C++ Build"
 
 on:
+  # always run on main branch
   push:
+    branches: [ main ]
     paths-ignore:
       - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'LICENSE'
+  # run on PR to main branch if relevant files changed
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'src/**'
+      - 'include/**'
+      - 'test/**'
+      - 'examples/**'
+      - 'CMakeLists.txt'
+      - '.github/workflows/cpp-build.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   build:

.github/workflows/cpp-lint.yml

@@ -1,9 +1,28 @@
 name: "C++ Lint"
 
 on:
+  # always run on main branch
   push:
+    branches: [ main ]
     paths-ignore:
       - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'LICENSE'
+  # run on PR to main branch if relevant files changed
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'src/**/*.cpp'
+      - 'include/**/*.h'
+      - 'test/**/*.cpp'
+      - 'test/**/*.h'
+      - 'examples/**/*.cpp'
+      - 'examples/**/*.h'
+      - '.github/workflows/cpp-lint.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   lint:

.github/workflows/cpp-unittest.yml

@@ -1,9 +1,27 @@
 name: "C++ Unittests"
 
 on:
+  # always run on main branch
   push:
+    branches: [ main ]
     paths-ignore:
       - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'LICENSE'
+  # run on PR to main branch if relevant files changed
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'src/**'
+      - 'include/**'
+      - 'test/**'
+      - 'CMakeLists.txt'
+      - '.github/workflows/cpp-unittest.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 
 jobs:
   unittest:

.github/workflows/format.yml

@@ -1,9 +1,25 @@
 name: "C++/CMake Format"
 
 on:
+  # always run on main branch
   push:
+    branches: [ main ]
     paths-ignore:
       - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'LICENSE'
+  # run on PR to main branch if relevant files changed
+  pull_request:
+    branches: [ main ]
+    paths:
+      - '**/*.cpp'
+      - '**/*.h'
+      - '**/CMakeLists.txt'
+      - '.github/workflows/format.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   format: