mark max1704x TAG const

[dankamongmen]

This allows us to use -wwrite-strings over the repo. Otherwise we get:

/home/dank/esp/build/_deps/espidflib-src/components/max1704x/max1704x.c:101:20: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
  101 | static char *TAG = "max1704x";
      |                    ^~~~~~~~~~

[trombik]

Do you think -wwrite-strings should be enabled by default?

[dankamongmen]

Do you think -wwrite-strings should be enabled by default?

absolutely

[dankamongmen]

but either way, this patch should be applied.

[dankamongmen]

also, leaving this out means projects which include this project using the standard ESP-IDF CMake mechanism (like my project =]) can't use -wwrite-strings, which is annoying.

[trombik]

@dankamongmen I am a co-maintainer of the repository and able to merge PRs. However, I always respect the repository owner's decision. So far, he has not commented. When he does, I will work on #663.

[dankamongmen]

no worries, @trombik !