feat(checksums): Add checksum for Erlang 26.2.5.21 (#21)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

data/erlang.json

@@ -109,6 +109,7 @@
   "26.2.5.18": "sha256-mCkJeRf6PsMsVJXBIpPoHMff5JyVXLSzPzCyLiJtgJo=",
   "26.2.5.19": "sha256-n9YQXuPmNtGin/+Sa9PBRfP9sNP6YfefCswzvEhYOlQ=",
   "26.2.5.20": "sha256-DEmqigZEMlqqQf71JLSjC0wmWYXprCyt6HOBvH8K/zw=",
+  "26.2.5.21": "sha256-z3MTcB6FZwIQW5GxM/gCe1UDonZXnDuyV2kLWuMcL2g=",
   "26.2.5.6": "sha256-5FsLAhbWqXjP18UQGNkbNQmFXlHiNoLY1aTzutLubZI=",
   "27.0": "sha256-YZWBLcpkm8B4sjoQO7I9ywXcmxXL+Dvq/JYsLsr7TO0=",
   "27.0.1": "sha256-Lp6J9eq6RXDi0RRjeVO/CIa4h/m7/fwOp/y0u0sTdFQ=",