updated readme to include steps on creating a new tag

README.md

 # go-utils
 A set of utilities used by our Golang projects
 * [errors](./errors/README.md)
+
+## Creating a new tag
+When making changes, a new tag needs to be made in order to use the updated library in your project. First pull the tags, and check the latest version.
+
+`git pull --tags`
+
+`git tag`
+
+The output will be a list of tags. Create a new tag with the version number increased. E.g. if the last tag was `v1.2.7`, the new tag could be `v1.2.8`. Then push the tag.
+
+`git tag -a v1.2.8 -m "Tag v1.2.8"`
+
+`git push --tags`
+
+For your project, upgrade to the new version by running the `go get` command.
+
+`go get gitlab.com/uafrica/go-utils@v1.2.8`
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