c2a: make Rust version matchin regex less exact

Allow custom version like 1.65.0.p1 (added in aosp/2404317).

Resolves warning:
WARNING: cannot find RustDefaultVersion in
development/scripts/../../build/soong/rust/config/global.go
Change-Id: I6fced7695473e025b0f739f9986df932d2c3f5fe

Test: cargo2android.py --config cargo2android.py
no warning

Change-Id: I43ff81f061477fc0322f27fef1c950954130dbc6
1 file changed