Update triggers for GitHub actions (#3)

.github/workflows/build.yml

@@ -1,6 +1,12 @@
 name: Build
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - "main"
+    tags:
+      - "v*"
 
 jobs:
   build_wheels:

.github/workflows/test.yml

@@ -1,6 +1,12 @@
 name: Test
 
-on: [push, pull_request]
+on:
+  pull_request:
+  push:
+    branches:
+      - "main"
+    tags:
+      - "v*"
 
 jobs:
   black: