github-ci: update commit and formatting containers

Update the Ubuntu containers for the commit and formatting checks to
Ubuntu 20.04.

The latest version of the checkout action requires git v2.18 in order to
checkout the code as a git repo, which is required for these workflows.

With older versions of git the action will download the code as a
tarball and lack the .git directory.

.github/workflows/commits.yml

@@ -5,12 +5,15 @@ on:
 
 permissions: read-all
 
+env:
+  DEBIAN_FRONTEND: "noninteractive"
+
 jobs:
 
   check-commits:
     name: Commit Check
     runs-on: ubuntu-latest
-    container: ubuntu:18.04
+    container: ubuntu:20.04
     steps:
       - name: Caching ~/.cargo
         uses: actions/cache@937d24475381cd9c75ae6db12cb4e79714b926ed
@@ -43,7 +46,7 @@ jobs:
                 libhiredis-dev \
                 libjansson-dev \
                 libevent-dev \
-                libevent-pthreads-2.1.6 \
+                libevent-pthreads-2.1-7 \
                 libjansson-dev \
                 libpython2.7 \
                 libssl-dev \
@@ -68,6 +71,8 @@ jobs:
           curl -OL https://github.com/eqrion/cbindgen/releases/download/v0.15.0/cbindgen
           chmod 755 cbindgen
       - uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
+        with:
+          fetch-depth: 0
       - run: git fetch
       - run: git clone https://github.com/OISF/libhtp -b 0.5.x
       - name: Building all commits

.github/workflows/formatting.yml

@@ -10,13 +10,16 @@ on:
 
 permissions: read-all
 
+env:
+  DEBIAN_FRONTEND: "noninteractive"
+
 jobs:
 
   # Checking for correct formatting of branch for C code changes
   check-formatting:
     name: Formatting Check (clang 9)
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
-    container: ubuntu:18.04
+    container: ubuntu:20.04
     continue-on-error: true
     steps:
 
@@ -83,6 +86,8 @@ jobs:
       # action to manually fix this up.
       - name: Checkout - might be merge commit!
         uses: actions/checkout@ec3a7ce113134d7a93b817d10a8272cb61118579
+        with:
+          fetch-depth: 0
         # Use last commit of branch, not potential merge commit!
         #
         # This works perfectly well on pull requests within forked repos, but