Replace egrep with grep -E

[unixorn]

Description

Per shellcheck, replace egrep with grep -E.

Type of changes

• Adds/updates a helper script
• Adds/updates a link to an external resource like a blog post or video
• Text change (fix typos, update formatting)
• Test changes

Copyright Assignment

• This document is covered by the Apache License, and I agree to contribute this PR under the terms of that license.

Checklist

• All new and existing tests pass.
• I have signed off my commits. You can use git commit --amend --no-edit --signoff to amend an existing commit, and you can find more details about signing off commits on the DCO GitHub action page here
• Any scripts added use #!/usr/bin/env interpreter instead of direct paths (#!/bin/sh is an allowed exception)
• Scripts are marked executable
• I have added/updated a credit line to README.md for any scripts added or updated in this PR
• If there was no author credit in a script added in this PR, I have added one.
• I have confirmed that the link(s) in my PR are valid.
• I have read the CONTRIBUTING document.

[codeclimate]

Code Climate has analyzed commit 11cb518 and detected 0 issues on this pull request.

View more on Code Climate.

[github-actions]

MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ COPYPASTE	jscpd	yes		no	0.93s
✅ CREDENTIALS	secretlint	yes		no	1.1s
✅ GIT	git_diff	yes		no	0.01s
✅ MARKDOWN	markdownlint	1		0	0.29s
✅ MARKDOWN	markdown-table-formatter	1		0	0.24s
✅ SPELL	misspell	3		0	0.03s

See errors details in artifact MegaLinter reports on CI Job page
Set VALIDATE_ALL_CODEBASE: true in mega-linter.yml to validate all sources, not only the diff