This pull request primarily introduces the 'ignore case' feature to the CLI application, allowing users to ignore case sensitivity in regular expressions. It also adds a new 'cover' target to the Makefile to generate a coverage report.

Here are the most important changes:

Addition of 'ignore case' feature:

• internal/cli/cli.go: Added a new ignoreCase field to the CLI struct [1]. This field is used to determine whether to ignore case sensitivity in regular expressions. The Run and parseFlags methods were updated to accommodate this new field [2] [3] [4]. The compileRegexps function was also modified to prefix all regular expressions with (?i) if ignoreCase is true [5].
• internal/cli/cli_test.go: Updated the tests to check the 'ignore case' feature. New test cases were added to TestRun_successProcess and TestCompileRegexps to test the functionality of the 'ignore case' feature [1] [2] [3]. The TestFilterProcess test was updated to use the new compileRegexps function signature [4].
• internal/cli/export_test.go: Updated the CompileRegexps function to use the new compileRegexps function signature.

Addition of 'cover' target in Makefile:

• Makefile: Added a new 'cover' target that generates a coverage report using go test -coverprofile and go tool cover -html.

Test data changes:

• internal/cli/testdata/test.txt: Added a new line with different casing to test the 'ignore case' feature.