Revert update to gRPC v1.27.0
This MR reverts changes introduced by !1960 (merged), which updated gRPC tools from v1.0.1 to v1.27.0. The change introduces issues with various setups, most notably with CentOS 6 (omnibus-gitlab#5232 (closed)) and musl-based Linux distributions like Alpine Linux (#2662 (closed)). As a result, the equivalent change in the GitLab repository was reverted already in gitlab!29102 (merged). Let's do the same for Gitaly to fix the issues.
Fixes #2662 (closed)
Edited by GitLab Release Tools Bot