build(deps): bump indexmap from 1.3.2 to 1.4.0

Bumps [indexmap](https://github.com/bluss/indexmap) from 1.3.2 to 1.4.0.
- [Release notes](https://github.com/bluss/indexmap/releases)
- [Commits](indexmap-rs/indexmap@1.3.2...1.4.0)

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

Author: dependabot-preview[bot]

Cargo.lock

@@ -7,7 +7,7 @@ edition = "2018"
 futures01 = { package="futures", version="0.1.29" }
 graph = { path = "../graph" }
 graphql-parser = "0.2.3"
-indexmap = "1.3"
+indexmap = "1.4"
 Inflector = "0.11.3"
 lazy_static = "1.2.0"
 uuid = { version = "0.8.1", features = ["v4"] }