gitlog2changelog.py fails with non-default Git configuration #487

Describe the bug

When trying to build the main branch, gitlog2changelog.py failed with:

Traceback (most recent call last):
  File "$SPACK_STAGE/spack-src/script/gitlog2changelog.py", line 55, in <module>
    date = dateList[1]
           ~~~~~~~~^^^
IndexError: list index out of range

This seems to be due to my .gitconfig containing:

[format]
  pretty = fuller

To Reproduce

Requires: spack/spack#36268

$ spack install environment-modules@main target=x86_64

Expected behavior

gitlog2changelog.py should also work with non-default configurations.

Error and debugging information

n/a

Modules version and configuration

n/a

Additional context

n/a