Bump apollo-link-http from 1.5.14 to 1.5.15 (#5701)

Bumps [apollo-link-http](https://github.com/apollographql/apollo-link) from 1.5.14 to 1.5.15.
- [Release notes](https://github.com/apollographql/apollo-link/releases)
- [Changelog](https://github.com/apollographql/apollo-link/blob/master/CHANGELOG.md)
- [Commits](https://github.com/apollographql/apollo-link/compare/[email protected]@1.5.15)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

package-lock.json

@@ -63,7 +63,7 @@
     "apollo-cache-inmemory": "1.6.2",
     "apollo-client": "2.6.3",
     "apollo-link": "1.2.12",
-    "apollo-link-http": "1.5.14",
+    "apollo-link-http": "1.5.15",
     "apollo-link-ws": "1.0.18",
     "apollo-upload-client": "10.0.1",
     "apollo-utilities": "1.2.1",