fix: upgrade @actions/github to 8.0.1 and @actions/core to 2.0.3 to resolve undici CVEs #1050

Job	Run time
Run Fuzz Checks (yaml)	9m 8s
Formatting check (cargo fmt)	20s
Testing Install Script (install-guard.sh) (macos-latest)	7s
Shellcheck	4s
Testing Windows Install Script (install-guard.ps1)	20s
Linting check (clippy)	25s
Build all crates & run unit tests (ubuntu-latest)	2m 59s
Build all crates & run unit tests (macos-latest)	5m 8s
Build all crates & run unit tests (windows-latest)	5m 32s
Integration tests against aws-guard-rules-registry for Windows	3m 30s
Testing Install Script (install-guard.sh) (ubuntu-latest)	6s
Integration tests against aws-guard-rules-registry (macos-latest)	1m 24s
Spell Check with Typos	6s
Integration tests against aws-guard-rules-registry (ubuntu-latest)	1m 35s
Run Fuzz Checks (guard_dsl)	9m 6s
	39m 50s

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