Lintian tag information: python3-script-but-no-python3-dep (type: error)

Description (from lintian-explain-tags)

Packages with Python3 scripts should depend on the package python3. Those
with scripts that specify a specific version of Python3 must depend,
recommend or suggest on that version of Python3 (exactly).

For example, if a script in the package uses #!/usr/bin/python3, the
package needs a dependency on python3. If a script uses
#!/usr/bin/python3.8, the package needs a dependency on python3.8. A
dependency on python (>= 3.8) is not correct, since later versions of
Python may not provide the /usr/bin/python3.8 binary.

If you are using debhelper, adding ${python3:Depends} to the Depends field
and ensuring dh_python3 is run during the build should take care of adding
the correct dependency.

In some cases a weaker relationship, such as Suggests or Recommends, will
be more appropriate.

Visibility: error
Show-Always: no
Check: scripts

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