Fix deprecated method

[boskiv]

╰─○ go run main.go 
# github.com/create-go-app/fiber-go-template/pkg/routes
pkg/routes/swagger_route.go:15:17: undefined: swagger.Handler

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Which issues are fixed by this PR?

Pre-launch Checklist

• [x] I have read and fully accepted project's code of conduct.
• [x] I listed at least one issue that this PR fixes in the description above.
• [x] I updated/added relevant documentation and/or comments to the code.
• [x] All existing and new tests are passing successfully.

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