Function update 

pub fn update(cfg: &Config, opts: UpdateOpts) -> Result<UpdateReport, PkgError>

Refresh deps and bump tag pins as appropriate, then re-install.

Walks [deps] (or just opts.name), classifies each entry via the decision table below, and — unless opts.dry_run — applies the changes:

dep pin	force	outcome
rev = "..."	any	Skipped("rev pin")
branch = "..."	any	Refresh
tag = "...", exact	false	Skipped("exact tag pin …")
tag = "...", exact	true	TagBumped (or Skipped("already at …"))
tag = "...", prefix	any	PrefixResolved (or Skipped("no match"))
tag = "...", junk	any	Skipped("tag '…' is not SemVer")
no pin	any	Refresh

TagBumped rewrites the manifest’s tag value in place through toml_edit (comments / key order preserved). Anything other than Skipped triggers a full install afterwards.

Errors

• PkgError::UnknownDep when opts.name is not in [deps].
• PkgError::ManifestEdit when the manifest cannot be re-parsed or the [deps.<name>] table is not editable.
• Anything install can return.