dependabot npm(deps): bump grpc-tools from 1.12.3 to 1.12.4

Bumps grpc-tools from 1.12.3 to 1.12.4.

Release notes

Sourced from grpc-tools's releases.

grpc-tools 1.12.4

• Add support for arm64 linux. (#2333 contributed by @​RedstoneWizard08)

Commits

• e6ea6f5 Merge pull request #2341 from murgatroid99/grpc-tools_1.12.4
• a86cb96 grpc-tools: Bump version to 1.12.4
• 8fd930b Merge pull request #2333 from RedstoneWizard08/master
• 4b9e401 Fix CMake args
• 71bfcd2 Fix static linking and dockerfile
• 3ec6114 Merge branch 'master' of https://github.com/grpc/grpc-node
• fe4272e Merge pull request #2339 from murgatroid99/grpc-js-xds_unit_tests
• 5732ff9 grpc-js-xds: Allow tests to set bootstrap info in channel args
• 05bebcd grpc-js-xds: Add unit test framework
• 877d4a6 Fix "file" command not found
• Additional commits viewable in compare view