revert to cortex-rt v0.5.0

Cargo.toml

@@ -14,7 +14,7 @@ vcell = "0.1.0"
 
 [dependencies.cortex-m-rt]
 optional = true
-version = "0.4.0"
+version = "0.5.0"
 
 [features]
 rt = ["cortex-m-rt/device"]
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