bug: invalid memory address or nil pointer dereference at getFileSHA()

[daniel-hutao]

Describe the Bug

invalid memory address or nil pointer dereference at getFileSHA()

2021/12/28 13:18:02 language is go-1.17
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x12bbfc7e0]

goroutine 1 [running]:
github.com/merico-dev/stream/internal/pkg/githubactions.(*GithubActions).getFileSHA(0x1400006a7e0, {0x12bc03c3c, 0xe})
	github.com/merico-dev/stream/internal/pkg/githubactions/githubactions.go:125 +0x1a0
github.com/merico-dev/stream/internal/pkg/githubactions.(*GithubActions).DeleteWorkflow(0x1400006a7e0, 0x140001c65d0)
	github.com/merico-dev/stream/internal/pkg/githubactions/githubactions.go:80 +0x60
github.com/merico-dev/stream/internal/pkg/githubactions.Uninstall(0x14000113c10)
	github.com/merico-dev/stream/internal/pkg/githubactions/uninstall.go:17 +0x218
github.com/merico-dev/stream/cmd/githubactions.Plugin.Uninstall({0x0, 0x0}, 0x14000113c10)
	github.com/merico-dev/stream/cmd/githubactions/main.go:27 +0x34
github.com/merico-dev/stream/internal/pkg/pluginengine.Uninstall(0x14000113bf0)
	github.com/merico-dev/stream/internal/pkg/pluginengine/plugin.go:42 +0xd4
github.com/merico-dev/stream/internal/pkg/planmanager.(*Plan).Execute(0x14000113b60)
	github.com/merico-dev/stream/internal/pkg/planmanager/plan.go:61 +0x3b0
main.installCMDFunc(0x10348b980, {0x1400006a3e0, 0x0, 0x2})
	github.com/merico-dev/stream/cmd/devstream/install.go:45 +0x318
github.com/spf13/cobra.(*Command).execute(0x10348b980, {0x1400006a3c0, 0x2, 0x2})
	github.com/spf13/cobra@v1.2.1/command.go:860 +0xa04
github.com/spf13/cobra.(*Command).ExecuteC(0x10348bc00)
	github.com/spf13/cobra@v1.2.1/command.go:974 +0x7b8
github.com/spf13/cobra.(*Command).Execute(0x10348bc00)
	github.com/spf13/cobra@v1.2.1/command.go:902 +0x30
main.main()
	github.com/merico-dev/stream/cmd/devstream/main.go:28 +0x30

Other notes

I've fixed this bug at #74 but it's reopen at #76 by "resolve conflict".

This is not a criticism of @lfbdev
Just remind us all that we should pay more attention at "avoid confict"/"resolve conflict"/"code review"

/kind bug
/cc @merico-dev/devstream