Mention the regex sensitivity of `commit_filter` strings
Mention the regex sensitivity of `commit_filter` strings

Polished the README to note that the `commit_filter` option is
sensitive to regex characters.  This was not immediately obvious and can
cause a bit of confusion.  Even leading to suspecting a defect in the
implementation of the filter as it can send the resource into a whacky
state of not selecting any commits (since the filter expression would
then be malformed).

Updated the README to mention this, and give an example of configuring
the `commit_filter.exclude` with a bracketed string that escapes the
bracket characters.

  commit_filter:
    exclude: ["\\[skip deploy\\]", "\\[deploy skip\\]"]

Lastly, also fixed a typo and removed the fully qualified dot notation
when describing the sub-elements of `commit_filter` in the README.

was:

  commit_filter:
    commit_filter.exclude:
    commit_filter_include:

now:

  commit_filter:
    exclude:
    include:

This aligns with the convention used in all other configuration options.

Only the README was changed in this commit.

Signed-off-by: Justin Griffin <c3316c820636ac14fec35fa50e41596df55530d1@ngc.com>

concourse/git-resource