deps: Add build recipe for GIF

[hisergiorojas]

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Description

As requested in https://github.com/AcademySoftwareFoundation/OpenImageIO/issues/4387.

Checklist:

• [ x] I have read the contribution guidelines.
• [ ] I have updated the documentation, if applicable. (Check if there is no need to update the documentation, for example if this is a bug fix that doesn't change the API.)
• [ ] I have ensured that the change is tested somewhere in the testsuite (adding new test cases if necessary).
• [ ] If I added or modified a C++ API call, I have also amended the corresponding Python bindings (and if altering ImageBufAlgo functions, also exposed the new functionality as oiiotool options).
• [ ] My code follows the prevailing code style of this project. If I haven't already run clang-format before submitting, I definitely will look at the CI test that runs clang-format and fix anything that it highlights as being nonconforming.