github: Update to Ubuntu 22.04

Move to the latest Ubuntu LTS for updated tooling. This requires us to
drop the zlibc package which no longer exists, and doesn't appear to be
required. Also update to the master branch of the GHDL action as this
contains 22.04 support.

Signed-off-by: Joel Stanley <joel@jms.id.au>

.github/workflows/ci.yml

@@ -4,7 +4,7 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
       # Checkout Repository
       - name: Checkout
@@ -13,7 +13,7 @@ jobs:
       - name: Setup CCache
         uses: hendrikmuhs/ccache-action@v1
 
-      - uses: ghdl/setup-ghdl-ci@nightly
+      - uses: ghdl/setup-ghdl-ci@master
         with:
           backend: llvm
 
@@ -22,7 +22,7 @@ jobs:
         run: |
           sudo apt-get install wget build-essential python3 ninja-build
           sudo apt-get install libevent-dev libjson-c-dev flex bison
-          sudo apt-get install libfl-dev libfl2 zlibc zlib1g-dev
+          sudo apt-get install libfl-dev libfl2 zlib1g-dev
           pip3 install setuptools
           pip3 install requests
           pip3 install pexpect