RFR: 8269601: Increase gcc-10 version for github workflow

[Johan Vos]

install latest version of gcc/g++ (older specific versions are not available anymore)

-------------

Commit messages:
 - fix #8269601

Changes: https://git.openjdk.java.net/jfx/pull/555/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=555&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269601
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/555.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/555/head:pull/555

PR: https://git.openjdk.java.net/jfx/pull/555