fix(github-actions): modify triggering conditions for workflows (#420)

.github/workflows/test.yml

@@ -1,5 +1,9 @@
 name: Test
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - main 
 
 jobs:
   release:

.github/workflows/test_docs.yml

@@ -1,6 +1,9 @@
 name: Test Docs
-on: [push, pull_request]
-
+on:
+  pull_request:
+  push:
+    branches:
+      - master
 jobs:
   release:
     runs-on: ubuntu-latest