Add Pg16 Support (#22)

* update cargo file, workflows and makefile

* update function signatures

* fix cargo fmt

* bump version

* add migration file

* address comment

* remove trailing comma for linter

.github/workflows/extension_ci.yml

@@ -47,8 +47,11 @@ jobs:
     if: github.event_name == 'release'
     name: trunk publish
     runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        pg: [ 14, 15, 16 ]
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install Rust stable toolchain
         uses: actions-rs/toolchain@v1
         with:
@@ -69,7 +72,7 @@ jobs:
           cargo install pg-trunk
       - name: trunk build
         working-directory: ./
-        run: trunk build
+        run: trunk build --pg-version ${{ matrix.pg }}
       - name: trunk publish
         working-directory: ./
         env: