chore: upgrade dependencies (#27)

Author: vasco-santos

package.json

@@ -43,15 +43,15 @@
   "homepage": "https://github.com/libp2p/js-libp2p-keychain#readme",
   "dependencies": {
     "async": "^2.6.1",
-    "interface-datastore": "~0.4.2",
+    "interface-datastore": "~0.6.0",
     "libp2p-crypto": "~0.13.0",
     "lodash": "^4.6.1",
     "pull-stream": "^3.6.8",
     "sanitize-filename": "^1.6.1"
   },
   "devDependencies": {
-    "aegir": "^14.0.0",
-    "chai": "^4.1.2",
+    "aegir": "^15.3.0",
+    "chai": "^4.2.0",
     "chai-string": "^1.4.0",
     "datastore-fs": "~0.5.0",
     "datastore-level": "~0.8.0",