Small update to readme

Author: JakeGinnivan

README.md

@@ -106,8 +106,9 @@ Uncomment and modify as you need.
 
 The configuration options are:
 
- - `?assembly-versioning-scheme`: When updating assembly info tells GitVersion how to treat the AssemblyVersion attribute. Useful to lock the major when using Strong Naming.
+ - `assembly-versioning-scheme`: When updating assembly info tells GitVersion how to treat the AssemblyVersion attribute. Useful to lock the major when using Strong Naming.
  - `mode`: Either ContinuousDelivery or ContinuousDeployment. See [Octopus Deploy/CI Build NuGet Packages](#continuousdeployment) above for more information
+ - `continuous-delivery-fallback-tag`: When using `mode: ContinuousDeployment` the value specified will be used as the pre-release tag for branches which do not have one specified.
  - `tag-prefix`: A regex which is used to trim git tags before processing (eg v1.0.0). Default is `[vV]` though this is just for illustrative purposes as we do a IgnoreCase match and could be `v`
 
 Then we have branch specific configuration, which looks something like this: