Initial bors-ng integration

Github Action only triggered on bors-ng controlled branches (trying/staging).
Fixes #324

.github/bors.toml

@@ -0,0 +1,6 @@
+status = [
+  "build-and-check", "clang-format"
+]
+# Uncomment this to use a two hour timeout.
+# The default is one hour.
+#timeout_sec = 7200

.github/workflows/ccpp.yml

@@ -2,12 +2,14 @@ name: C/C++ CI
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - trying
+      - staging
   pull_request:
     branches: [ master ]
 
 jobs:
-  build:
+  build-and-check:
 
     runs-on: ubuntu-latest
 

.github/workflows/clang-format.yml

@@ -2,12 +2,14 @@ name: Clang Format Lint
 
 on:
   push:
-    branches: [ master ]
+    branches:
+      - trying
+      - staging
   pull_request:
     branches: [ master ]
 
 jobs:
-  build:
+  clang-format:
     runs-on: ubuntu-latest
 
     steps: