Resolve issue with proc_macro_span_shrink

Author: sunsided

Cargo.toml

@@ -59,18 +59,13 @@ systick-monotonic = "1.0"
 usb-device = "0.3.2"
 usbd-serial = "0.2.2"
 
-# Unblock minimal dependency version check
-# [dependencies.proc-macro2]
-# version = ">=1.0.86"
-# default-features = false
-#
-# [dependencies.syn]
-# version = "2.0.68"
-# default-features = false
-
 [build-dependencies]
 slice-group-by = "0.3.1"
 
+# Unblock minimal dependency version check
+[dependencies.proc-macro2]
+version = ">1.0.60"
+
 [features]
 can = ["dep:bxcan"]
 default = ["rt", "ld", "usb", "can", "rtc", "enumset"]