Update documentation

Author: mrozanc

README.md

@@ -236,7 +236,9 @@ e.g `${dirty:-SNAPSHOT}` resolves to `-SNAPSHOT` instead of `-DIRTY`
 
 - `${describe}` Will resolve to `git describe` output
 - `${describe.distance}` The distance count to last matching tag
+- `${describe.distanceOrZero}` The distance count to last matching tag or 0 if no tag is found
 - `${describe.distance.snapshot}` Empty string on matching tag, `-SNAPSHOT` if `describe.distance > 0` 
+- `${describe.distanceOrZero.snapshot}` Empty string on matching tag, `-SNAPSHOT` if `describe.distanceOrZero > 0` 
 - `${describe.tag}` The matching tag of `git describe`
   - `${describe.tag.version}` the tag version determined by regex `(?<version>(?<core>(?<major>\d+)(?:\.(?<minor>\d+)(?:\.(?<patch>\d+))?)?)(?:-(?<label>.*))?)`
     - `${describe.tag.version.core}` the core version component of `${describe.tag.version}` e.g. '1.2.3' 
@@ -247,11 +249,15 @@ e.g `${dirty:-SNAPSHOT}` resolves to `-SNAPSHOT` instead of `-DIRTY`
     - `${describe.tag.version.patch}` the patch version component of `${describe.tag.version}` e.g. '3'
       - `${describe.tag.version.patch.next}` the `${describe.tag.version.patch}` increased by 1 e.g. '4'
       - `${describe.tag.version.patch.plus.describe.distance}` the `${describe.tag.version.patch}` increased by `${describe.distance}` e.g. '2'
+      - `${describe.tag.version.patch.plus.describe.distanceOrZero}` the `${describe.tag.version.patch}` increased by `${describe.distanceOrZero}` e.g. '2'
       - `${describe.tag.version.patch.next.plus.describe.distance}` the `${describe.tag.version.patch.next}` increased by `${describe.distance}` e.g. '3'
+      - `${describe.tag.version.patch.next.plus.describe.distanceOrZero}` the `${describe.tag.version.patch.next}` increased by `${describe.distanceOrZero}` e.g. '3'
     - `${describe.tag.version.label}` the label version component of `${describe.tag.version}` e.g. 'SNAPSHOT'
       - `${describe.tag.version.label.next}` the `${describe.tag.version.label}` converted to an integer and increased by 1 e.g. '6'
       - `${describe.tag.version.label.plus.describe.distance}` the `${describe.tag.version.label}` increased by `${describe.distance}` e.g. '2'
+      - `${describe.tag.version.label.plus.describe.distanceOrZero}` the `${describe.tag.version.label}` increased by `${describe.distanceOrZero}` e.g. '2'
       - `${describe.tag.version.label.next.plus.describe.distance}` the `${describe.tag.version.label.next}` increased by `${describe.distance}` e.g. '3'
+      - `${describe.tag.version.label.next.plus.describe.distanceOrZero}` the `${describe.tag.version.label.next}` increased by `${describe.distanceOrZero}` e.g. '3'
 - Describe Tag Pattern Groups
     - Content of regex groups in `<describeTagPattern>` can be addressed like this:
     - `${describe.tag.GROUP_NAME}` `${describe.tag.GROUP_NAME.slug}`