Add build_pr workflow to match master

.github/workflows/build_pr.yml

@@ -0,0 +1,24 @@
+name: Build PR
+
+on:
+    pull_request:
+        branches:
+            - master
+            - v5-lts
+
+jobs:
+    build:
+        runs-on: ubuntu-latest
+        steps:
+            -   uses: actions/checkout@v2.3.5
+            -   uses: actions/setup-dotnet@v4
+                with:
+                    dotnet-version: "8.0.x"
+            -   name: Build
+                run: |
+                    ./build.sh --target Publish
+            -   name: Upload Artifacts
+                uses: actions/upload-artifact@v4
+                with:
+                    path: "./bin/dist/*.zip"
+                    name: "BepInEx_CI"