Ignore invalid versions instead of panic

TL;DR: This change make binenv update ignoring invalid version names instead of failing with a panic.

I tried to add Hashicorp Packer tool in distributions and I found that it is not possible because of one of their releases (the nightly one). As you can see, this tool have a nightly version that can't be parsed correctly by the go-version library (a library from .... Hashicorp :upside_down_face: ).

Here is the result when you add those lines to distributions.yaml.

  packer:
    list:
      type: github-releases
      url: https://api.github.com/repos/hashicorp/packer/releases
    fetch:
      url: https://releases.hashicorp.com/packer/{{ .Version }}/packer_{{ .Version }}_{{ .OS }}_{{ .Arch }}.zip
    install:
      type: zip
      binaries:
        - packer

$ binenv update packer
updating distributions 100% || (1/1, 23640 it/s) [0s:0s]
panic: Malformed version: nightly

goroutine 1 [running]:
github.com/hashicorp/go-version.Must(...)
    /home/runner/go/pkg/mod/github.com/hashicorp/go-version@v1.2.1/version.go:104
github.com/devops-works/binenv/internal/app.(*App).updateLocally(0xc00010f7c0, 0xc0001cf060, 0x1, 0x1, 0x0, 0x0)
    /home/runner/work/binenv/binenv/internal/app/app.go:536 +0x9b5
github.com/devops-works/binenv/internal/app.(*App).Update(0xc00010f7c0, 0x0, 0xc0001cf060, 0x1, 0x1, 0x0, 0x0)
    /home/runner/work/binenv/binenv/internal/app/app.go:472 +0x359
github.com/devops-works/binenv/cmd.updateCmd.func1(0xc0001f22c0, 0xc0001cf060, 0x1, 0x1)
    /home/runner/work/binenv/binenv/cmd/update.go:22 +0x1d3
github.com/spf13/cobra.(*Command).execute(0xc0001f22c0, 0xc0001cf030, 0x1, 0x1, 0xc0001f22c0, 0xc0001cf030)
    /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:846 +0x2c2
github.com/spf13/cobra.(*Command).ExecuteC(0xc0001e9340, 0x0, 0x81d4a0, 0xc00006a058)
    /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:950 +0x375
github.com/spf13/cobra.(*Command).Execute(...)
    /home/runner/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:887
main.main()
    /home/runner/work/binenv/binenv/main.go:15 +0x2a

I suggest this little change in order to only ignore the malformed version instead of just "panics". Then the command will only print a message.

$ ./bin/binenv update packer
updating distributions 100% || (1/1, 29560 it/s) [0s:0s]
2020-10-05T18:08:32+02:00 WRN ignoring invalid version for "packer" error="Malformed version: nightly"

devops-works / binenv

Ignore invalid versions instead of panic #32