make resolc crate publishable (#334)

- Fetching the commit SHA must not panic if not executed in a git
repository.
- Remove the license printer.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

Cargo.lock

@@ -8533,7 +8533,7 @@ dependencies = [
 
 [[package]]
 name = "resolc"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "anyhow",
  "clap",