Bump version to 0.2.0

Introducing the alloc dependency by default is definitely semver-breaking

Author: eholk

Cargo.toml

@@ -4,7 +4,7 @@
 [package]
 name = "stackfuture"
 description = "StackFuture is a wrapper around futures that stores the wrapped future in space provided by the caller."
-version = "0.1.1"
+version = "0.2.0"
 edition = "2021"
 license = "MIT"
 authors = ["Microsoft"]