niv motoko-base: update 5bbf04cf -> 1f52c6b8 (#4179)

## Changelog for motoko-base:
Branch: next-moc
Commits: [dfinity/motoko-base@5bbf04cf...1f52c6b8](dfinity/motoko-base@5bbf04c...1f52c6b)

* [`452b7db7`](dfinity/motoko-base@452b7db) Bindings for adjacent fix-width numerical conversions and flesh out docs ([dfinity/motoko-base⁠#585](https://togithub.com/dfinity/motoko-base/issues/585))

nix/sources.json

@@ -76,10 +76,10 @@
         "homepage": null,
         "owner": "dfinity",
         "repo": "motoko-base",
-        "rev": "5bbf04cf82d9ffea685e91584d6e830e3e6f25f2",
-        "sha256": "16prry3hnr171a4w17jxd9f62r3ly7dwrg5pszz8yzxf1hmv3d6w",
+        "rev": "1f52c6b8fe64b15ae6ea68fc0fc2130b2112f6ce",
+        "sha256": "1vam0mbyia55a1ik8jylv1amvq8sm5ibshjcy8wkhzwmwqsjx35n",
         "type": "tarball",
-        "url": "https://github.com/dfinity/motoko-base/archive/5bbf04cf82d9ffea685e91584d6e830e3e6f25f2.tar.gz",
+        "url": "https://github.com/dfinity/motoko-base/archive/1f52c6b8fe64b15ae6ea68fc0fc2130b2112f6ce.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "motoko-matchers": {