Update required Go version in BUILDING.md
Our main branch no longer builds successfully with Go 1.17.
@@ -14,7 +14,7 @@ This doc includes:
To build the `containerd` daemon, and the `ctr` simple test client, the following build system dependencies are required:
-* Go 1.17.x or above
+* Go 1.18.x or above
* Protoc 3.x compiler and headers (download at the [Google protobuf releases page](https://github.com/protocolbuffers/protobuf/releases))
* Btrfs headers and libraries for your distribution. Note that building the btrfs driver can be disabled via the build tag `no_btrfs`, removing this dependency.
