feat: Remove CI job based on Ubuntu 18.04 (#2375)

* feat: Remove CI job based on Ubuntu 18.04

* feat: Remove CI job based on Ubuntu 18.04

Removed extra comments

.github/workflows/release.yml

@@ -236,14 +236,6 @@ jobs:
               extra-build-args: "",
               flutter_profile: production-linux-x86_64,
             }
-          # - { arch: aarch64, target: aarch64-unknown-linux-gnu, os: ubuntu-20.04, extra-build-args: "", flutter_profile: production-linux-aarch64 }
-          - {
-              arch: x86_64,
-              target: x86_64-unknown-linux-gnu,
-              os: ubuntu-18.04,
-              extra-build-args: "",
-              flutter_profile: production-linux-x86_64,
-            }
     steps:
       - name: Checkout source code
         uses: actions/checkout@v3