chore: remove ubuntu 20 as its deprected by github, will build manually

Author: abose

.github/workflows/tauri-build-dev.yml

@@ -280,7 +280,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        platform: [ ubuntu-20.04, ubuntu-22.04]
+        platform: [ ubuntu-22.04]
 
     runs-on: ${{ matrix.platform }}
     steps:

.github/workflows/tauri-build-prod.yml

@@ -329,7 +329,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        platform: [ ubuntu-20.04, ubuntu-22.04]
+        platform: [ ubuntu-22.04]
 
     runs-on: ${{ matrix.platform }}
     steps:

.github/workflows/tauri-build-staging.yml

@@ -280,7 +280,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        platform: [ ubuntu-20.04, ubuntu-22.04]
+        platform: [ ubuntu-22.04]
 
     runs-on: ${{ matrix.platform }}
     steps: