chore: fix VERSIONS motoko label (v1.8.0 → v1.8.2) (#278)

## Summary

- Corrects the `motoko` label in `.sources/VERSIONS` from `v1.8.0` to
`v1.8.2` to match the actual pinned submodule commit (`b77651f`, which
is 2 commits ahead of the v1.8.2 tag)
- Prevents the `sync-motoko` workflow from opening false-positive bump
PRs (it compares VERSIONS against the latest release tag; the stale
label was causing it to see `v1.8.0 ≠ v1.8.2` and trigger a PR even
though the submodule was already at or ahead of v1.8.2)

## Sync recommendation

`hand-written`

Author: marc0olo

.sources/VERSIONS

@@ -57,7 +57,7 @@ chain-fusion-signer   v0.3.0
 papi                  v0.1.1                                                    168bc9d
 ic-pub-key            v1.0.1                                                    f89fa55
 icp-cli               v0.2.3                                                    caeac37
-motoko                v1.8.0                                                     75c4123
+motoko                v1.8.2                                                     b77651f
 motoko-core           v2.4.0                                                    cd37dbf
 cdk-rs                ic-cdk v0.20.1 / ic-cdk-timers v1.0.0 / ic-cdk-executor v2.0.0  317f55c
 candid                2025-12-18  # candid v0.10.20, didc v0.5.4                2e4a2cf