Typo in ProjectSpec.md (#1405)

schems -> schemes

It ain't much, but it's honest work 😄

Docs/ProjectSpec.md

@@ -68,7 +68,7 @@ You can also use environment variables in your configuration file, by using `${S
 - [ ] **targets**: **[String: [Target](#target)]** - The list of targets in the project mapped by name
 - [ ] **fileGroups**: **[String]** - A list of paths to add to the root of the project. These aren't files that will be included in your targets, but that you'd like to include in the project hierarchy anyway. For example a folder of xcconfig files that aren't already added by any target sources, or a Readme file.
 - [ ] **schemes**: **[Scheme](#scheme)** - A list of schemes by name. This allows more control over what is found in [Target Scheme](#target-scheme)
-- [ ] **schemeTemplates**: **[String: [Scheme Template](#scheme-template)]** - a list of schemes that can be used as templates for actual schems which reference them via a `template` property. They can be used to extract common scheme settings. Works great in combination with `include`.
+- [ ] **schemeTemplates**: **[String: [Scheme Template](#scheme-template)]** - a list of schemes that can be used as templates for actual schemes which reference them via a `template` property. They can be used to extract common scheme settings. Works great in combination with `include`.
 - [ ] **targetTemplates**: **[String: [Target Template](#target-template)]** - a list of targets that can be used as templates for actual targets which reference them via a `template` property. They can be used to extract common target settings. Works great in combination with `include`.
 - [ ] **packages**: **[String: [Swift Package](#swift-package)]** - a map of Swift packages by name.
 - [ ] **projectReferences**: **[String: [Project Reference](#project-reference)]** - a map of project references by name