CI: add libpq-dev for PostgreSQL linking

.forgejo/workflows/botserver.yaml

@@ -34,6 +34,11 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-cargo-botserver-
 
+      - name: Install system dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libpq-dev libssl-dev liblzma-dev
+
       - name: Install Rust
         run: |
           curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y