Version constraints configuration

terraform-docs version constraints is almost identical to the syntax
used by Terraform. A version constraint is a string literal containing
one or more condition, which are separated by commas.

```yaml
version: ">= 0.13.0, < 1.0.0"
```

Each condition consists of an operator and a version number. A version
number is a series of numbers separated by dots (e.g. `0.13.0`). Note
that version number should not have leading `v` in it.

Valid operators are as follow:

- `=` (or no operator): allows for exact version number.
- `!=`: exclude an exact version number.
- `>`, `>=`, `<`, and `<=`: comparisons against a specific version.
- `~>`: only the rightmost version component to increment.

Signed-off-by: Khosrow Moossavi <khos2ow@gmail.com>

examples/.terraform-docs.yml

@@ -1,4 +1,9 @@
+# # terraform-docs version constraints for execution
+# # more information: https://terraform-docs.io/user-guide/configuration/#version
+# version: ">= 0.10, < 0.12"
+
 formatter: markdown table
+
 header-from: doc.txt
 footer-from: footer.md