fix: make version dynamic based on Git tag

[snghnaveen]

Description :

• Replaced static version string with Git tag during build
• Version is now set dynamically using 'git describe --tags' during compilation
• Ensures that the version always reflects the latest Git tag

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Testing output :

17:37:26 ~/code/gogen fix-version-tag $ make build-all                    
GOOS=linux GOARCH=amd64 go build -ldflags "-X github.com/luigimorel/gogen/cmd.Tag=v0.4.4" -o bin/gogen-linux-amd64 ./main.go
GOOS=darwin GOARCH=amd64 go build -ldflags "-X github.com/luigimorel/gogen/cmd.Tag=v0.4.4" -o bin/gogen-darwin-amd64 ./main.go
GOOS=darwin GOARCH=arm64 go build -ldflags "-X github.com/luigimorel/gogen/cmd.Tag=v0.4.4" -o bin/gogen-darwin-arm64 ./main.go
GOOS=windows GOARCH=amd64 go build -ldflags "-X github.com/luigimorel/gogen/cmd.Tag=v0.4.4" -o bin/gogen-windows-amd64.exe ./main.go

17:37:29 ~/code/gogen fix-version-tag $ ./bin/gogen-darwin-arm64 --version
gogen version v0.4.4