chore: Add github action for building and testing

Author: if-loop69420

.github/workflows/build_test.yaml

@@ -0,0 +1,21 @@
+name: Cargo Build & Test
+
+on:
+  push:
+  pull_request:
+
+env: 
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build_and_test:
+    name: Rust project - latest
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: rustup update stable && rustup default stable
+      - run: cargo install cargo-pgrx --version 0.16.0
+      - run: cargo build --verbose
+      - run: cargo pgrx test --verbose
+  
+