Disable unnecessary actions

Author: nikolai-laevskii

.github/workflows/build.yml

@@ -1,7 +1,9 @@
 name: Build
 
 on:
-  pull_request:
+  push:
+    branches:
+      - master
 
 concurrency:
   group: ci-build-${{ github.ref }}-1

.github/workflows/spelling.yml

@@ -1,5 +1,8 @@
 name: Check spelling
-on: [pull_request]
+on:
+  push:
+    branches:
+      - master
 jobs:
   misspell:
     name: Check spelling

.github/workflows/test.yml

@@ -1,7 +1,9 @@
 name: "Test"
 
 on:
-  pull_request:
+  push:
+    branches:
+      - master
 
 concurrency:
   group: ci-tests-${{ github.ref }}-1