[C++] Update IWYU version in the `lint` dockerfile

[asfimport]

I was trying to cleanup the c++ imports based on the current docker-iwyu suggestions, but it requires to be customized (symbol maps and pragmas) more than it is currently. It'd also help a lot to use the latest IWYU version (see the changelog https://include-what-you-use.org/)

Reporter: Krisztian Szucs / @kszucs
Assignee: Wes McKinney / @wesm

Related issues:

• [C++] IWYU docker image silently fails (duplicates)

PRs and other links:

• GitHub Pull Request #3643

_{Note: This issue was originally created as ARROW-4340. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
This probably needs to be updated now that we're on LLVM 7

[asfimport]

Francois Saint-Jacques / @fsaintjacques:
Note that ubuntu provided iwyu (the package) is still linked with llvm-5 and the compiler used within arrow has no effect on this. Having support for the latest IWYU would imply compiling from source locally, unless someone can point to a binary release, I do not have time to add this for now as I fear I'll enter rabit whole.

[asfimport]

Wes McKinney / @wesm:
I just put up a patch. Please help by periodically looking at the IWYU report.

Be careful about what you change – there are some weird things it reports that will break MSVC if you change them. We probably will need to tweak the mappings files now and then

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 3643
#3643