Add bindgen to PR template

[kneth]

What, How & Why?

☑️ ToDos

• 📝 Changelog update
• 🚦 Tests (or not relevant)
• C-API, if public C++ API changed.

[coveralls-official]

Pull Request Test Coverage Report for Build github_pull_request_283741

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 80 unchanged lines in 13 files lost coverage.
• Overall coverage increased (+0.004%) to 91.668%

---

Files with Coverage Reduction	New Missed Lines	%
src/realm/array_string.cpp	2	88.0%
src/realm/db.cpp	2	93.72%
src/realm/object-store/shared_realm.cpp	2	93.74%
src/realm/query_engine.hpp	2	94.17%
src/realm/sync/changeset.hpp	2	73.49%
src/realm/table_view.cpp	2	94.18%
src/realm/util/file.cpp	2	81.73%
src/realm/sort_descriptor.cpp	3	93.7%
src/realm/sync/noinst/protocol_codec.hpp	3	76.72%
src/realm/unicode.cpp	4	90.15%

Totals
Change from base Build 1819:	0.004%
Covered Lines:	230810
Relevant Lines:	251790

---

💛 - Coveralls