fix(sec): upgrade github.com/gin-gonic/gin to 1.7.7

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What happened？

There are 1 security vulnerabilities found in github.com/gin-gonic/gin v1.7.2

• CVE-2020-28483

What did I do？

Upgrade github.com/gin-gonic/gin from v1.7.2 to 1.7.7 for vulnerability fix

What did you expect to happen？

Ideally, no insecure libs should be used.

The specification of the pull request

PR Specification from OSCS