fix outdated ubuntu version that no longer seems to be available on github actions

Author: DetachHead

.github/workflows/publish_vscode.yml

@@ -23,14 +23,14 @@ jobs:
           - os: windows-latest
             target: aarch64-pc-windows-msvc
             code-target: win32-arm64
-          - os: ubuntu-20.04
+          - os: ubuntu-latest
             target: x86_64-unknown-linux-gnu
             code-target: linux-x64
-          - os: ubuntu-20.04
+          - os: ubuntu-latest
             target: aarch64-unknown-linux-gnu
             code-target: linux-arm64
             arch: aarch64
-          - os: ubuntu-20.04
+          - os: ubuntu-latest
             target: arm-unknown-linux-gnueabihf
             code-target: linux-armhf
             arch: armv7