Use a definite version specification when depending on pyo3-build-config.

We already do this for other internal pyo3-* dependencies and it seems prudent
to apply this to pyo3-build-config as well.

Author: adamreichold

Cargo.toml

@@ -57,7 +57,7 @@ rayon = "1.6.1"
 widestring = "0.5.1"
 
 [build-dependencies]
-pyo3-build-config = { path = "pyo3-build-config", version = "0.20.1", features = ["resolve-config"] }
+pyo3-build-config = { path = "pyo3-build-config", version = "=0.20.1", features = ["resolve-config"] }
 
 [features]
 default = ["macros"]

pyo3-ffi/Cargo.toml

@@ -38,7 +38,7 @@ abi3-py312 = ["abi3", "pyo3-build-config/abi3-py312"]
 generate-import-lib = ["pyo3-build-config/python3-dll-a"]
 
 [build-dependencies]
-pyo3-build-config = { path = "../pyo3-build-config", version = "0.20.1", features = ["resolve-config"] }
+pyo3-build-config = { path = "../pyo3-build-config", version = "=0.20.1", features = ["resolve-config"] }
 
 [lints]
 workspace = true