Bump proc-macro2 to unbreak nightly #1685

Job	Run time
clippy_check (ubuntu-latest, stable)	46s
clippy_check (ubuntu-latest, nightly)	1m 3s
clippy_check (windows-latest, stable)	2m 40s
clippy_check (windows-latest, nightly)	2m 3s
Rustfmt (stable)	12s
Build and Test (ubuntu-latest, 1.60)	4m 9s
Build and Test (ubuntu-latest, 1.65)	3m 47s
Build and Test (ubuntu-latest, stable)	6m 3s
Build and Test (ubuntu-latest, beta)	2m 49s
Build and Test (ubuntu-latest, nightly)	3m 23s
Build and Test (windows-latest, 1.60)	7m 30s
Build and Test (windows-latest, 1.65)	5m 21s
Build and Test (windows-latest, stable)	6m 49s
Build and Test (windows-latest, beta)	4m 6s
Build and Test (windows-latest, nightly)	6m 1s
Tests result	1s
	56m 43s

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