update workflows

Author: thednp

.github/workflows/ci.yml

@@ -1,5 +1,10 @@
 name: ci
-on: push
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - src
 jobs:
   test:
     runs-on: ubuntu-20.04

.github/workflows/codeql.yml

@@ -14,9 +14,15 @@ name: "CodeQL"
 on:
   push:
     branches: [ master ]
+    paths:
+      - src
+      - .github/workflows/codeql.yml
   pull_request:
     # The branches below must be a subset of the branches above
     branches: [ master ]
+    paths:
+      - src
+      - .github/workflows/codeql.yml
 
 jobs:
   analyze: