Add `storage-subdirectory` input

[walkowif]

Closes https://github.com/insightsengineering/coverage-action/issues/35

[github-actions[bot]]

Code Coverage Summary (test-missing-lines.xml)

Filename                Stmts    Miss  Cover    Missing
--------------------  -------  ------  -------  ---------------
all_lines_covered.py       10       0  100.00%
miss_at_start.py           10       2  80.00%   1-3
miss_at_end.py             10       2  80.00%   9-10
single_line_gaps.py        10       3  70.00%   3, 5, 9
multi_line_gaps.py         10       7  30.00%   4-5, 7-9, 15-18
unsorted_lines.py          10       5  50.00%   4, 3, 8-9, 6
no_lines.py                 0       0  0.00%
single_line.py              1       1  0.00%    4
TOTAL                      61      20  51.25%

Results for commit: a40e3fa7197312fa6592957276ac5e95600bee6c

Minimum allowed coverage is 50%

:recycle: This comment has been updated with latest results

[github-actions[bot]]

Code Coverage Summary (test-no-branch.xml)

Filename                          Stmts    Miss  Cover    Missing
------------------------------  -------  ------  -------  ---------
Main.java                            11       0  100.00%
search/BinarySearch.java             12       1  91.67%   24
search/ISortedArraySearch.java        0       0  100.00%
search/LinearSearch.java              7       2  71.43%   19-24
TOTAL                                30       3  90.00%

Diff against main

Filename      Stmts    Miss  Cover
----------  -------  ------  --------
TOTAL             0       0  +100.00%

Results for commit: a40e3fa7197312fa6592957276ac5e95600bee6c

Minimum allowed coverage is 90%

:recycle: This comment has been updated with latest results

[walkowif]

@cicdguy Thanks for the review, I think I addressed all your comments.