feat: Add GitHub Actions for PNG generation and GoReleaser

Adds two GitHub Actions workflows:

- A workflow to automatically regenerate the `vim-barcodes-a4.png` file when any Go file is modified on the main branch. This ensures the PNG is always up-to-date with the code.

- A GoReleaser workflow that triggers on new version tags (e.g., v1.2.3) to create a new release with binaries for multiple platforms, including .deb and .rpm packages.

Also adds a `.goreleaser.yml` configuration file to customize the release process. The Go version for the workflows is dynamically determined from the `go.mod` file.

Author: google-labs-jules[bot]

.goreleaser.yml

@@ -31,7 +31,7 @@ nfpms:
     id: "vim-barcode-sheet"
     package_name: "vim-barcode-sheet"
     homepage: "https://github.com/arran4/vim-barcode-sheet"
-    maintainer: "Arran Ubels <[email protected]>"
+    maintainer: "Arran Ubels <[email protected].au>"
     description: "Vim barcode sheet generator."
     license: "MIT"
     formats: