Cache FDB packages during the build and avoid checking them in (#3164)

This is to prevent another build from failing to produce a PR on
unsuccessful merge (see #3163). It removes the debian packages from the
working directory, and it also excludes `*.deb` files in the
`.gitignore`, just to be sure. While I was there, I also added artifact
caching so that the directory would be included in the build cache.
There may not be much of a difference, given that the artifacts being
downloaded are hosted on GitHub anyway, but it seemed like a good
practice.

Author: alecgrieser

.gitignore

@@ -4,6 +4,7 @@
 *.jar
 *.war
 *.ear
+*.deb
 
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*

actions/setup-fdb/action.yml

@@ -9,15 +9,28 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: Download FDB Client
+    - name: Set FDB Filenames
+      id: fdb_filenames
       shell: bash
-      run: wget -nv https://github.com/apple/foundationdb/releases/download/${{ inputs.fdb_version }}/foundationdb-clients_${{ inputs.fdb_version }}-1_amd64.deb
-    - name: Download FDB Server
+      run: |
+        echo "client_deb=foundationdb-clients_${{ inputs.fdb_version }}-1_amd64.deb" >> "${GITHUB_OUTPUT}"
+        echo "server_deb=foundationdb-server_${{ inputs.fdb_version }}-1_amd64.deb" >> "${GITHUB_OUTPUT}"
+    - name: Check FDB Binaries Cache
+      id: cache_fdb
+      uses: actions/cache@v3
+      with:
+        path: ~/.fdb-cache
+        key: ${{ runner.os }}-fdb-debs-${{ inputs.fdb_version }}
+    - name: Download FDB Binaries
+      if: steps.cache_fdb.outputs.cache-hit != 'true'
       shell: bash
-      run: wget -nv https://github.com/apple/foundationdb/releases/download/${{ inputs.fdb_version }}/foundationdb-server_${{ inputs.fdb_version }}-1_amd64.deb
+      run: |
+        mkdir -p ~/.fdb-cache
+        wget -O ~/.fdb-cache/${{ steps.fdb_filenames.outputs.client_deb }} -nv https://github.com/apple/foundationdb/releases/download/${{ inputs.fdb_version }}/${{ steps.fdb_filenames.outputs.client_deb }}
+        wget -O ~/.fdb-cache/${{ steps.fdb_filenames.outputs.server_deb }} -nv https://github.com/apple/foundationdb/releases/download/${{ inputs.fdb_version }}/${{ steps.fdb_filenames.outputs.server_deb }}
     - name: Install FDB Server
       shell: bash
-      run: sudo dpkg -i foundationdb-clients_${{ inputs.fdb_version }}-1_amd64.deb foundationdb-server_${{ inputs.fdb_version }}-1_amd64.deb
+      run: sudo dpkg -i ~/.fdb-cache/${{ steps.fdb_filenames.outputs.client_deb }} ~/.fdb-cache/${{ steps.fdb_filenames.outputs.server_deb }}
     - name: Fix FDB Network Addresses
       shell: bash
       run: sudo sed -i -e "s/public_address = auto:\$ID/public_address = 127.0.0.1:\$ID/g" -e "s/listen_address = public/listen_address = 0.0.0.0:\$ID/g" /etc/foundationdb/foundationdb.conf