Fixes #1874 - Upgrade regex dependency to 1.5.6

[martin-g]

Which issue does this PR close?

Closes #1874.

Rationale for this change

Use newer version of regex dependency which does not have (known) vulnerabilities.

What changes are included in this PR?

Upgrade a dependency.

Are there any user-facing changes?

No.

[codecov-commenter]

Codecov Report

Merging #1875 (413f393) into master (cedaf8a) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1875      +/-   ##
==========================================
- Coverage   83.46%   83.46%   -0.01%     
==========================================
  Files         201      201              
  Lines       57014    57014              
==========================================
- Hits        47586    47585       -1     
- Misses       9428     9429       +1     

Impacted Files	Coverage Δ
parquet_derive/src/parquet_field.rs	65.98% <0.00%> (-0.23%)	⬇️

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[tustvold]

I checked the changelog and no major excitement, so looks good to me. Thank you

Edit: I'll run the benchmarks later this evening to double check no major performance regression

[tustvold]

Benchmarking egexp_matches_utf8 scalar starts with: Warming up for 3.0000 s
Warning: Unable to complete 100 samples in 5.0s. You may wish to increase target time to 6.0s, enable flat sampling, or reduce sample count to 60.
egexp_matches_utf8 scalar starts with                                                                             
                        time:   [1.1939 ms 1.1944 ms 1.1949 ms]
                        change: [-0.2673% -0.2043% -0.1392%] (p = 0.00 < 0.05)
                        Change within noise threshold.
Found 7 outliers among 100 measurements (7.00%)
  2 (2.00%) low mild
  2 (2.00%) high mild
  3 (3.00%) high severe

Benchmarking egexp_matches_utf8 scalar ends with: Warming up for 3.0000 s
Warning: Unable to complete 100 samples in 5.0s. You may wish to increase target time to 7.0s, enable flat sampling, or reduce sample count to 50.
egexp_matches_utf8 scalar ends with                                                                             
                        time:   [1.3771 ms 1.3777 ms 1.3784 ms]
                        change: [+0.0456% +0.1435% +0.2443%] (p = 0.00 < 0.05)
                        Change within noise threshold.
Found 4 outliers among 100 measurements (4.00%)
  3 (3.00%) high mild
  1 (1.00%) high severe

Looks good

(not sure why this is egexp not regexp...)