230630.235154.CST update README

Former-commit-id: 9e9e66a6713039341c3c2d1f673836493d5f7aae

Author: zaikunzhang

README.md

@@ -112,8 +112,8 @@ periodically to verify that the solvers work correctly without running into erro
 **excessively large problems**.
 
 The tests are **automated** by
-[GitHub Actions](https://docs.github.com/en/actions). As of June 2023, more than
-42,000 "workflows" have been successfully run by GitHub Actions. Normally, each workflow consists of \~ 5
+[GitHub Actions](https://docs.github.com/en/actions). As of July 2023, more than
+45,000 "workflows" have been successfully run by GitHub Actions. Normally, each workflow consists of \~ 5
 ([sometimes more than 150](https://github.com/primalib/prima/actions/runs/5260791888))
 **randomized** tests,
 each test taking from tens of minutes to several hours (the maximum