Bump ajv from 4.11.8 to 6.12.6

Bumps [ajv](https://github.com/ajv-validator/ajv) from 4.11.8 to 6.12.6.
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@4.11.8...v6.12.6)

---
updated-dependencies:
- dependency-name: ajv
  dependency-type: indirect
...

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

Author: dependabot[bot]

package-lock.json

@@ -3,13 +3,12 @@
 
 
 ajv@^6.5.5:
-  version "6.12.1"
-  resolved "https://registry.npmjs.org/ajv/-/ajv-6.12.1.tgz"
+  version "6.12.6"
+  resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
   dependencies:
     fast-deep-equal "^3.1.1"
     fast-json-stable-stringify "^2.0.0"
     json-schema-traverse "^0.4.1"
-    opencollective-postinstall "^2.0.2"
     uri-js "^4.2.2"
 
 align-text@^0.1.1, align-text@^0.1.3:
@@ -157,12 +156,12 @@ extsprintf@1.3.0, extsprintf@^1.2.0:
   resolved "https://registry.npmjs.org/extsprintf/-/extsprintf-1.3.0.tgz"
 
 fast-deep-equal@^3.1.1:
-  version "3.1.1"
-  resolved "https://registry.npmjs.org/fast-deep-equal/-/fast-deep-equal-3.1.1.tgz"
+  version "3.1.3"
+  resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-3.1.3.tgz#3a7d56b559d6cbc3eb512325244e619a65c6c525"
 
 fast-json-stable-stringify@^2.0.0:
   version "2.1.0"
-  resolved "https://registry.npmjs.org/fast-json-stable-stringify/-/fast-json-stable-stringify-2.1.0.tgz"
+  resolved "https://registry.yarnpkg.com/fast-json-stable-stringify/-/fast-json-stable-stringify-2.1.0.tgz#874bf69c6f404c2b5d99c481341399fd55892633"
 
 forever-agent@~0.6.1:
   version "0.6.1"
@@ -235,7 +234,7 @@ jsbn@~0.1.0:
 
 json-schema-traverse@^0.4.1:
   version "0.4.1"
-  resolved "https://registry.npmjs.org/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz"
+  resolved "https://registry.yarnpkg.com/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz#69f6a87d9513ab8bb8fe63bdb0979c448e684660"
 
 json-schema@0.2.3:
   version "0.2.3"
@@ -329,10 +328,6 @@ oauth-sign@~0.9.0:
   version "0.9.0"
   resolved "https://registry.npmjs.org/oauth-sign/-/oauth-sign-0.9.0.tgz"
 
-opencollective-postinstall@^2.0.2:
-  version "2.0.2"
-  resolved "https://registry.npmjs.org/opencollective-postinstall/-/opencollective-postinstall-2.0.2.tgz"
-
 pandoc-filter@0.1.6:
   version "0.1.6"
   resolved "https://registry.npmjs.org/pandoc-filter/-/pandoc-filter-0.1.6.tgz"
@@ -487,8 +482,8 @@ underscore@1.7.0:
   resolved "https://registry.npmjs.org/underscore/-/underscore-1.7.0.tgz"
 
 uri-js@^4.2.2:
-  version "4.2.2"
-  resolved "https://registry.npmjs.org/uri-js/-/uri-js-4.2.2.tgz"
+  version "4.4.1"
+  resolved "https://registry.yarnpkg.com/uri-js/-/uri-js-4.4.1.tgz#9b1a52595225859e55f669d928f88c6c57f2a77e"
   dependencies:
     punycode "^2.1.0"