Bump mem from 6.0.1 to 6.1.1

Bumps [mem](https://github.com/sindresorhus/mem) from 6.0.1 to 6.1.1.
- [Release notes](https://github.com/sindresorhus/mem/releases)
- [Commits](sindresorhus/memoize@v6.0.1...v6.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -30,7 +30,7 @@
     "koa": "^2.11.0",
     "koa-router": "^8.0.8",
     "koa-send": "^5.0.0",
-    "mem": "^6.0.1",
+    "mem": "^6.1.1",
     "mime-types": "^2.1.26",
     "nile": "git+https://github.com/ovsoinc/node-nile.git",
     "nodemon": "^2.0.3",