Add .gitattributes.

[Oberon00]

This fixes spotlessCheck when checking out on windows with git core.eol=crlf and core.autocrlf=true.

Note that for git itself, the eol=lf next to the text=auto changes nothing, but spotless tries to
enforce the core.eol line endings anyway.

Use https://github.com/open-telemetry/opentelemetry-java/pull/1798/files?w=1 (note the ?w=1) to verify that only whitespace (line endings) is changed in the batch files.

[codecov]

Codecov Report

Merging #1798 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1798      +/-   ##
============================================
+ Coverage     85.53%   85.56%   +0.03%     
  Complexity     1374     1374              
============================================
  Files           166      166              
  Lines          5308     5308              
  Branches        549      549              
============================================
+ Hits           4540     4542       +2     
+ Misses          569      568       -1     
+ Partials        199      198       -1     

Impacted Files	Coverage Δ	Complexity Δ
...try/sdk/metrics/aggregator/LongMinMaxSumCount.java	100.00% <0.00%> (+4.08%)	6.00% <0.00%> (ø%)

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[jkwatson]

Thanks! I can't evaluate if this will help windows users or not, but if you say so, then 👍

[Oberon00]

I think you should be able to reproduce the issue on non-Windows by using git config core.eol crlf && git config core.autocrlf true inside your checkout.

[anuraaga]

Yeah I think we need a gitattributes file I always have issues on windows without it.

@Oberon00 What do you think about a simpler one like we use in instrumentation repo?

https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/master/.gitattributes

[trask]

+1 to having the same .gitattributes file across both repos (if there is something you think we are missing in instrumentation repo we can update there)

[Oberon00]

The simpler one should also be fine.

[Oberon00]

That said, I think at least the -text should be kept for safety.

[anuraaga]

Thanks!

[jkwatson]

closing and reopening for the CLA bot