* replace ccache with sccache, pin package versions
* put ccache back temporarily to avoid breaking other CI jobs
* add sccashe_wrapper.sh script
* fix the package version syntax
* fix the pymysql package issue
* run sccache_wrapper before build if ccache server found
* set the paths before calling the sccache_wrapper
* use /tmp instead of /usr/local for cache
* try using sccache --start-server instead of wrapper
* try using redis server with sccache
* define SCCACHE_REDIS
* add redis and ping packages, and redis port
* use the new sccache redis server
* do not use sccache with staging compiler
* fix the condition syntax
* add stunnel to redis
* add tunnel verification
* separate caches for different architectures
* fix syntax for the cache tag
* quse double brackets for conditions
* add bash line to the script
* add a switch for sccache and only use it in build stage
* run check_host function when enabling sccache
* fix the invocation tags for sccache
* fix groovy syntax
* set the invocation tag in groovy
* disable sccache in clang-format stage
* try another syntax for invocation tags
* use local sccache server if can't connect to redis
* fix script syntax
* update README
* refresh readme
* readme updates
* remove the timing and verification caveat from readme
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Co-authored-by: Lisa Delaney <lisa.delaney@amd.com>
