fix ci runner to not use snapd

.gitea/workflows/tests.yml

@@ -13,11 +13,17 @@ jobs:
       - name: Install Neovim
         run: |
           sudo apt-get update
-          sudo apt-get install -y snapd
-          sudo systemctl enable --now snapd.socket
-          sudo systemctl start snapd
-          sudo snap wait system seed.loaded
-          sudo snap install nvim --classic
+          sudo apt-get install -y curl xz-utils
+          ARCH=$(uname -m)
+          if [ "$ARCH" = "aarch64" ]; then
+            APPIMAGE="nvim-linux-arm64.appimage"
+          else
+            APPIMAGE="nvim-linux-x86_64.appimage"
+          fi
+          curl -L -o "$APPIMAGE" "https://github.com/neovim/neovim/releases/latest/download/$APPIMAGE"
+          chmod +x "$APPIMAGE"
+          "./$APPIMAGE" --appimage-extract
+          sudo mv squashfs-root/usr/bin/nvim /usr/local/bin/nvim
 
       - name: Install plenary.nvim
         run: |