Release 0.45.0 (#797)

Including the following features from gapic-generator:
- Java: generate tests using the non-flattening overload if an rpc does not have flattening configuration (#3087)
- Generate method overloads when a resource field has multiple resource associated (#3081)
- Fix generated code for changing the timeout. (#3078)
- bazel: Add support for prebuilt PHP binaries (#3079)
- Add multi-pattern resource check for C# (#3080)

Including the following features from proto-java-resource-names-plugin:
- Support multi-pattern resource name with child_type

Dockerfile

@@ -5,7 +5,7 @@ ENV GOOGLEAPIS_HASH e47fdd266542386e5e7346697f90476e96dc7ee8
 ENV GAPIC_GENERATOR_HASH cdfe1fc4bb43c0571cf3b780681108f215a76758
 # Define version number below. The ARTMAN_VERSION line is parsed by
 # .circleci/config.yml and setup.py, please keep the format.
-ENV ARTMAN_VERSION 0.44.4
+ENV ARTMAN_VERSION 0.45.0
 
 ENV DEBIAN_FRONTEND noninteractive