dependabot npm(deps): bump @grpc/proto-loader from 0.7.6 to 0.7.7

Bumps @grpc/proto-loader from 0.7.6 to 0.7.7.

Release notes

Sourced from @​grpc/proto-loader's releases.

@​grpc/proto-loader 0.7.7

• Update yargs dependency to 17.x (#2437)

Commits

• 892f16e Merge pull request #2437 from murgatroid99/proto-loader_yargs_update
• 821ccfa PSM Interop: Increase old driver QPS to 75
• bc2447c proto-loader: Update to yargs@17.x
• eeaa6c0 Merge pull request #2434 from murgatroid99/v1.8.x_upmerge
• 85d227b Update test logic to account for recent validation changes
• 2f86949 Update tests with master test framework changes
• d70d7ee Merge remote-tracking branch 'upstream/@grpc/grpc-js@1.8.x' into v1.8.x_upmerge
• 4fcd9c2 Merge pull request #2433 from murgatroid99/grpc-js-xds_watcher_validation_errors
• edeeda6 Add trailing newline in packages/grpc-js-xds/test/test-nack.ts
• dfccd68 Address review comments
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