Update RegExUtil.java

[LouisdeLooze]

Updating theme regex to support dashes.

Description (*)
According to the Magento devdocs:

The folder name conventionally matches naming used in the theme's code: any alphanumeric set of characters, as the vendor sees fit, is acceptable. This convention is merely a recommendation, so nothing prevents naming this directory in another way.

The current regex limits the themes to:

match	group	is_participating	start	end	content
1	0	yes	0	21	frontend/Vendor/theme
2	0	yes	44	74	frontend/Vendor/custom9_theme9
3	0	yes	106	136	frontend/Vendor/custom9_theme9
4	0	yes	137	159	frontend/Vendor/custom
5	0	yes	196	225	frontend/Vendor/custom9Theme9

The adapted regex allows the themes to be:

match	group	is_participating	start	end	content
1	0	yes	0	21	frontend/Vendor/theme
2	0	yes	22	43	frontend/Vendor/Theme
3	0	yes	44	74	frontend/Vendor/custom9_theme9
4	0	yes	75	105	frontend/Vendor/Custom9_theme9
5	0	yes	106	136	frontend/Vendor/custom9_theme9
6	0	yes	137	165	frontend/Vendor/custom-theme
7	0	yes	166	195	frontend/Vendor/Custom9Theme9
8	0	yes	196	225	frontend/Vendor/custom9Theme9
9	0	yes	226	247	frontend/vendor/theme
10	0	yes	248	269	frontend/vendor/Theme
11	0	yes	270	300	frontend/vendor/custom9_theme9
12	0	yes	301	331	frontend/vendor/Custom9_theme9
13	0	yes	332	362	frontend/vendor/custom9_theme9
14	0	yes	363	391	frontend/vendor/custom-theme
15	0	yes	392	421	frontend/vendor/Custom9Theme9
16	0	yes	422	451	frontend/vendor/custom9Theme9

Thanks @sdouma for the regex!

Fixed Issues (if relevant)

1. Fixes Custom theme couldn't be detected #1517

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with integration/functional tests (if applicable)
• All automated tests passed successfully (all builds are green)

[VitaliyBoyko]

@LouisdeLooze thank you for your contribution.
Could you please check tests?

[LouisdeLooze]

Hi @VitaliyBoyko
Just tried running the test again locally from both clean branches,

• 5.3.0 -> no issues
• 5.4.0 -> all tests fail because of aNullPointerException
  Tried to revert back the build.gradle and all test pass again. Seems that o be a deeper issue...

[VitaliyBoyko]

@LouisdeLooze thank you. Will check it. Could you please create a backport PR to the 5.3.1-develop branch?