Avoid duplicate CI runs on push+PR (#125)

Author: jishnub

.github/workflows/ci.yml

@@ -1,7 +1,17 @@
 name: CI
 on:
-  - push
-  - pull_request
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'LICENSE'
+      - 'README.md'
+      - '.github/workflows/TagBot.yml'
+  pull_request:
+    paths-ignore:
+      - 'LICENSE'
+      - 'README.md'
+      - '.github/workflows/TagBot.yml'
 
 concurrency:
   group: build-${{ github.event.pull_request.number || github.ref }}