Update version to v1.18.0

[willhickey]

Nothing in this commit except the version bump:

$ glol -1
997c3ec91b 2023-10-02 11:43:37 -0500  (HEAD -> version_update_v1.18)  will.hickey@solana.com Update version to v1.18.0
$ git diff master..HEAD | grep -vE "^ |^@@ |^--- |^\+\+\+ |^index |^diff |^-( \")?solana.*1.17.0|^\+( \")?solana.*1.18.0|^-version|^\+version"
$

[codecov]

Codecov Report

Merging #33487 (997c3ec) into master (660e41a) will increase coverage by 0.0%.
Report is 3 commits behind head on master.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #33487   +/-   ##
=======================================
  Coverage    81.7%    81.7%           
=======================================
  Files         802      802           
  Lines      217786   217786           
=======================================
+ Hits       178082   178099   +17     
+ Misses      39704    39687   -17