build(deps): update indoc requirement from 1.0 to 2.0

Updates the requirements on [indoc](https://github.com/dtolnay/indoc) to permit the latest version.
- [Release notes](https://github.com/dtolnay/indoc/releases)
- [Commits](https://github.com/dtolnay/indoc/compare/1.0.0...2.0.0)

---
updated-dependencies:
- dependency-name: indoc
  dependency-type: direct:production
...

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

xtask/Cargo.toml

@@ -11,6 +11,6 @@ anyhow = "1"
 syn = "1"
 quote = "1"
 proc-macro2 = "1"
-indoc = "1.0"
+indoc = "2.0"
 lazy_static = "1"
 serde_json = "1"