This is an initial implementation of writing locks back to a file on disk.
This initial implementation is incomplete because it does not write the
changes to the new file atomically. We'll revisit that in a later commit
as we return to polish these codepaths, once we've proven out this
package's design by integrating it with Terraform's provider installer.
This is the initial implementation of the parser/decoder portion of the
new dependency lock file handler. It's currently dead code because the
caller isn't written yet. We'll continue to build out this functionality
here until we have the basic level of both load and save functionality
before introducing this into the provider installer codepath.