add tags for major and minor versions

[arichtman]

Adds additional tags for major and minor versions

Closes #30

[ozbillwang]

this change has been rollbacked, since we start supporting opentofu in this image,

For examples, below tags are supported now:

• alpine/terragrunt:latest
• alpine/terragrunt:1.8.4 (terraform version)
• alpine/terragrunt:tf1.8.4 (terraform version)
• alpine/terragrunt:otf1.7.1 (opentofu version)

[arichtman]

@ozbillwang Would you be open to a PR to implement loose tags for the new tags?