dappnodesdk may be run in a non-initialized git repo

[Lion - dapplion]

When running dappnodesdk in a directory without an initialized git repo it logs an error message

$ dappnodesdk build -p remote
  ✔ Verify connection
  ✔ Create release dir
  ✔ Copy files and validate
  ✔ Build docker image
  ⠴ Save and compress image
    → 623,9 KiB / 1.432,0 KiB = 0,436
    Upload release to IPFS node
    Save upload results
Error on getGitHead Error: Command failed: git rev-parse --verify HEAD
fatal: no es un repositorio git (ni ninguno de los directorios superiores): .git

  ✔ Verify connection                                                                                      ✔ Create release dir
  ✔ Copy files and validate
  ✔ Build docker image
  ✔ Save and compress image
  ✔ Upload release to IPFS node

It should not log that message and test if the git directory exists first