RFR: CODETOOLS-7903172: Change invocation of GitHub Actions

[Jonathan Gibbons]

Update the events for GitHub Actions to better align with JDK.

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Commit messages:
 - CODETOOLS-7903172: Change invocation of GitHub Actions

Changes: https://git.openjdk.java.net/jtreg/pull/81/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jtreg&pr=81&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903172
  Stats: 6 lines in 1 file changed: 0 ins; 3 del; 3 mod
  Patch: https://git.openjdk.java.net/jtreg/pull/81.diff
  Fetch: git fetch https://git.openjdk.java.net/jtreg pull/81/head:pull/81

PR: https://git.openjdk.java.net/jtreg/pull/81