fix: support binary rename patches

[nornagon]

example from the wild: https://chromium.googlesource.com/chromium/src/+/22b5144060f40e96f2e7faba8d5c15a288f6d0f7%5E%21/

diff --git a/chrome/android/java/res_autofill_assistant/drawable-hdpi/autofill_assistant_bottombar_bg.9.png b/chrome/android/features/autofill_assistant/java/res/drawable-hdpi/autofill_assistant_bottombar_bg.
9.png
similarity index 100%
rename from chrome/android/java/res_autofill_assistant/drawable-hdpi/autofill_assistant_bottombar_bg.9.png
rename to chrome/android/features/autofill_assistant/java/res/drawable-hdpi/autofill_assistant_bottombar_bg.9.png
Binary files differ

This is currently failing with a parse error.

[BinaryMuse]

In #12, I wrote:

The binary field is usually true or false, but in this case, we don't actually know if the file is binary or not, so I opted to set this to null.

But perhaps I was mistaken, as shown in this diff. @kuychaco, do you think we should add the binary field for items processed by postProcessSimilarityDiff?

[BinaryMuse]

The diffs I generated for the tests in #12 includes e.g.

diff --git old/file.png new/file.png
similarity index 90%
rename from old/file.png
rename to new/file.png
diff --git copy/file.png copy/file2.png
similarity index 100%
copy from copy/file.png
copy to copy/file2.png

I need to double check if these are accurate Git output for copies/renames of binary files.

[BinaryMuse]

In any case, this looks good to me as a starting point.

[nornagon]

I'm not sure how Gitiles is generating its output, but what I am parsing is https://chromium.googlesource.com/chromium/src/+/74.0.3724.8..74.0.3729.5?format=TEXT (which is a base64-encoded patch generated by gitiles)