Bump version to 2.0.0

PiperOrigin-RevId: 529178781
Change-Id: I1ee5acc77940af6e2254520d0331f77eae21b45a

Author: morambro

README.md

@@ -15,6 +15,8 @@ Tink (Bazel) | [![Bazel_GcpUbuntu][tink_cc_awskms_bazel_badge_gcp_ubuntu]](#) |
 This is an extension to the [Tink C++](https://github.com/tink-crypto/tink-cc)
 library that provides support for AWS KMS.
 
+The latest version is 2.0.0.
+
 The official documentation is available at https://developers.google.com/tink.
 
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