Bump version to 4.3-dev #3

Job	Run time
📊 Static checks / Code style, file formatting, and docs	2m 40s
🤖 Android / Template (target=template_release)	27m 54s
🍏 iOS / Template (target=template_release)	29m 26s
🌐 Web / Template (target=template_release)	19m 59s
🐧 Linux / Editor w/ Mono (target=editor)	32m 43s
🍎 macOS / Editor (target=editor, tests=yes)	41m 48s
🍎 macOS / Template (target=template_release)	22m 52s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	35m 57s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	29m 28s
🐧 Linux / Editor with ThreadSanitizer (target=editor, tests=yes, dev_build=yes, use_tsan=yes, use_llvm=yes, linker=lld)	25m 58s
🐧 Linux / Template w/ Mono (target=template_release)	21m 46s
🏁 Windows / Editor (target=editor, tests=yes)	38m 55s
🐧 Linux / Minimal template (target=template_release, everything disabled)	13m 41s
🏁 Windows / Template (target=template_release)	28m 32s
🪲 Godot CPP / Build and test Godot CPP	6m 47s
	6h 18m 26s

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