Update build.yml

Commit 71a5ceb removed `pull_request` from the build workflow, but that should not have been done.

Author: aristotelos

.github/workflows/build.yml

@@ -2,6 +2,7 @@ name: build
 
 on:
   push:
+  pull_request:
 
 jobs:
   build:
@@ -49,4 +50,4 @@ jobs:
       uses: softprops/action-gh-release@v2
       if: startsWith(github.ref, 'refs/tags/')
       with:
-        files: ./src/FlaUI.WebDriver/bin/Release/win-x64/publish/*.*
+        files: ./src/FlaUI.WebDriver/bin/Release/win-x64/publish/*.*