Change ubuntu version to 20.04 (#91)

* Change ubuntu version to 20.04

Author: michelu89

.github/workflows/codeql-scanning.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   analyze:
     name: Analyze
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     permissions:
       actions: read
       contents: read

.github/workflows/push_request_check.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   build:
     name: Check if passes all requirements
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
       - name: Checkout project

.github/workflows/tagged_release.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ macos-latest, windows-latest, ubuntu-latest ]
+        os: [ macos-latest, windows-latest, ubuntu-20.04 ]
 
     steps:
       - name: Checkout project

documentation/ame-guide/modules/ROOT/pages/system-requirements.adoc

@@ -29,7 +29,6 @@ To use the Aspect Model Editor on Mac, you need:
 
 To use the Aspect Model Editor on Linux, you need:
 
-* 64-bit Ubuntu 18.04+, Debian 10+, openSUSE 15.2+, or Fedora Linux 32+
+* 64-bit Ubuntu 20.04+, Debian 10+, openSUSE 15.2+, or Fedora Linux 32+
 * An Intel Pentium 4 processor or later that is SSE3-capable
-
-
+* The executable requires GLIBC of the specified version or a newer one.