Update wails in go.sum

[mareksapota]

Summary: Fixes mismatch in wails version between go.mod and go.sum. Fixes the following issue with vendoring mods:

Before:

$ go mod vendor && echo success
go: github.com/wailsapp/wails@v1.16.7: missing go.sum entry for go.mod file; to add it:
        go mod download github.com/wailsapp/wails

After:

$ go mod vendor && echo success
success

[mareksapota]

Hey, @fdidron could you take a look at this? For more context I'm packaging Wally for openSUSE. The Go tooling for openSUSE packages uses vendored in dependencies (see here and here for more details) and fails to produce the vendor tar due to the go mod vendor error shown above. Fixing this issue would make packaging easier, currently I'm forced to build Wally from my own branch (the one attached to this PR). The code in this PR has been generated by running the command suggested in the error message: go mod download github.com/wailsapp/wails.