Update Golang to 1.14

No longer ignore ~/.aws/config (AWS)

• #2 Add validation of required flags

• distribution packaging [mac - linux] #8 - mac only
• Add GPG support #9

• fix calculating magic number for Azure provider

• use Azure CLI to obtain credentials for Azure Key Vault
• add Azure KeyVault integration test
• include metadata header with KeyVault key information in encrypted file
• add --indir and --outdir options
• improve logging

• fixed #11 - encrypt adds a new line

• parametrize AWS API credentials profile
• add interfaces: Crypter, Encrypter, Decrypter
• bump golang version to 1.12