Change default SAI version to 1.18.1 for OSS

Summary: Bump the OSS/getdeps default SAI version to 1.18.1 (libsai manifest, CMakeLists, build-helper.py, fboss_oss_build.bzl, container docs). run-getdeps.py already lists 1.18.1 in SAI_VERSION_SHAS, so it needs no change.

Reviewed By: shri-khare, daiwei1983

Differential Revision: D113351959

fbshipit-source-id: a8f9bb0cd1d8dc15d684a3b305f4915e26916aa4

Author: simuthus-fb

build/fbcode_builder/manifests/libsai

@@ -2,12 +2,12 @@
 name = libsai
 
 [download]
-url = https://github.com/opencomputeproject/SAI/archive/v1.16.3.tar.gz
-sha256 = 5c89cdb6b2e4f1b42ced6b78d43d06d22434ddbf423cdc551f7c2001f12e63d9
+url = https://github.com/opencomputeproject/SAI/archive/v1.18.1.tar.gz
+sha256 = 84f2fbd6bf672abaefddfd78a28fec794e37477bf9702fbb56d7bd53ff930ba3
 
 [build]
 builder = nop
-subdir = SAI-1.16.3
+subdir = SAI-1.18.1
 
 [install.files]
 inc = include