Fix CI failure with i386 caused by latest Ubuntu version. Pin Ubuntu version to allow us to upgrade in the future. (#56447)

Fixes this CI failure on all new PRs.
Pins our version so we don't immediately fail next time something like this happens.

.github/workflows/ci_suite.yml

@@ -10,7 +10,7 @@ jobs:
   run_linters:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
     name: Run Linters
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - name: Setup cache
@@ -44,7 +44,7 @@ jobs:
   compile_all_maps:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
     name: Compile Maps
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - name: Setup cache
@@ -63,7 +63,7 @@ jobs:
   run_all_tests:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
     name: Integration Tests
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     services:
       mysql:
         image: mysql:latest
@@ -90,7 +90,7 @@ jobs:
         run: |
           sudo dpkg --add-architecture i386
           sudo apt update || true
-          sudo apt install libssl1.1:i386
+          sudo apt install -o APT::Immediate-Configure=false libssl1.1:i386
           bash tools/ci/install_rust_g.sh
       - name: Compile and run tests
         run: |

.github/workflows/compile_changelogs.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   compile:
     name: "Compile changelogs"
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: "Check for CHANGELOG_ENABLER secret and pass true to output if it exists to be checked by later steps"
         id: value_holder

.github/workflows/docker_publish.yml

@@ -8,7 +8,7 @@ on:
 jobs:
   publish:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
 

.github/workflows/generate_documentation.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   generate_documentation:
     if: "!contains(github.event.head_commit.message, '[ci skip]')"
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
       - name: Setup cache

.github/workflows/round_id_linker.yml

@@ -5,7 +5,7 @@ on:
 
 jobs:
   link_rounds:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - uses: tgstation/round_linker@master
       with:

.github/workflows/stale.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   stale:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
     - uses: actions/stale@v1

.github/workflows/update_tgs_dmapi.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   update-dmapi:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     name: Update the TGS DMAPI
     steps:
     - name: Clone