Update indoc requirement from 1.0.3 to 2.0.1

Updates the requirements on [indoc](https://github.com/dtolnay/indoc) to permit the latest version.
- [Release notes](https://github.com/dtolnay/indoc/releases)
- [Commits](dtolnay/indoc@1.0.3...2.0.1)

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

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

Cargo.toml

@@ -25,7 +25,7 @@ pyo3-ffi = { path = "pyo3-ffi", version = "=0.19.0" }
 
 # support crates for macros feature
 pyo3-macros = { path = "pyo3-macros", version = "=0.19.0", optional = true }
-indoc = { version = "1.0.3", optional = true }
+indoc = { version = "2.0.1", optional = true }
 unindent = { version = "0.1.4", optional = true }
 
 # support crate for multiple-pymethods feature