fix: fix v5-related errors (#178)

Signed-off-by: Phil Adams <phil_adams@us.ibm.com>

.bumpversion.cfg

@@ -3,7 +3,7 @@ current_version = 5.12.2
 commit = True
 message = Update version numbers from {current_version} -> {new_version} [skip ci]
 
-[bumpversion:file:v5/core/version.go]
+[bumpversion:file:core/version.go]
 search = __VERSION__ = "{current_version}"
 replace = __VERSION__ = "{new_version}"
 

CONTRIBUTING.md

@@ -63,7 +63,7 @@ If you want to contribute to the repository, here's a quick guide:
      Others might be added in the future.
      To run a specific class of tests (example 'retries'), use a command like this:
      ```
-     cd v5/core
+     cd core
      go test -tags=retries
      ```
      

README.md

@@ -1,6 +1,6 @@
 [![Build Status](https://app.travis-ci.com/IBM/go-sdk-core.svg?branch=main)](https://app.travis-ci.com/IBM/go-sdk-core)
 [![Release](https://img.shields.io/github/v/release/IBM/go-sdk-core)](https://github.com/IBM/go-sdk-core/releases/latest)
-![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/IBM/go-sdk-core?filename=v5/go.mod)
+![GitHub go.mod Go version](https://img.shields.io/github/go-mod/go-version/IBM/go-sdk-core?filename=go.mod)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
 [![CLA assistant](https://cla-assistant.io/readme/badge/ibm/go-sdk-core)](https://cla-assistant.io/ibm/go-sdk-core)