This is needed to avoid auto-updater script warnings.
Also it is needed to avoid this error:
```
INFO: Updating dcmtk [Current version: 3.6.7]
Traceback (most recent call last):
File "<stdin>", line 5, in <module>
File "/usr/lib/python3/dist-packages/pkg_resources/_vendor/packaging/version.py", line 266, in __init__
raise InvalidVersion(f"Invalid version: '{version}'")
pkg_resources.extern.packaging.version.InvalidVersion: Invalid version: 'DCMTK-3.6.7'
INFO: No update needed. Already at version 'DCMTK-3.6.7'.
```
Does not depend on libicu, in favor of libiconv:
```
-- Info: Both ICU and the libiconv are available, using libiconv. Modify DCMTK_ENABLE_CHARSET_CONVERSION for switching to ICU
-- Info: Building DCMTK with character set conversion support using libiconv
```
%ci:no-build
