Update web-service-gin to newer way of adding modules

[princefishthrower]

Hi, I was following this tutorial using Go 1.17 and saw that using go get . doesn't work to install the github.com/gin-gonic/gin module. I followed this stack overflow: https://stackoverflow.com/questions/69025385/go-1-14-to-1-17-update-modules-not-working-anymore and found that go mod tidy correctly added the module for me. Obviously open to wording, refactoring, reconsideration changes

[princefishthrower]

Actually I may stand corrected, while go mod tidy allowed github.com/gin-gonic/gin to be imported, I still couldn't run the example. It turns out it is the latest github.com/gin-gonic/gin module that is the issue. There is an open issue with v1.7.5, so the fix (for now) is go get github.com/gin-gonic/[email protected]