cgirgen: remove the `var` expression fixup #5630

Job	Run time
Provide additional context for the workflow	1s
Build source archive	0s
Build and test (${{ matrix.target.name }})	0s
Package from Git (macOS (M1)) / Build release artifacts	5m 6s
Package from Git (macOS) / Build release artifacts	8m 49s
Package from Git (Linux) / Build release artifacts	10m 29s
Package from Git (Windows) / Build release artifacts	18m 0s
Package from archive (${{ matrix.target.name }})	0s
Test release artifacts	0s
All check passed	0s
	42m 25s

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