Update build-and-test.yml (#48)

Remove push run.
diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index 3012de5..423d705 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -1,8 +1,6 @@
 name: Build and test
 
 on:
-  push:
-    branches: [ "main" ]
   pull_request:
     branches: [ "main" ]