chore: update cargo-deny config to v2

New configuration layouts were introduced for _advisories_ and
_licenses_ sections. These will become the default at some point and
it's good to adopt early.

deny.toml

@@ -1,7 +1,18 @@
+[graph]
 all-features = true
 
+[advisories]
+version = 2
+
 [licenses]
-allow-osi-fsf-free = "both"
+version = 2
+allow = [
+	"Apache-2.0",
+	"BSD-2-Clause",
+	"BSD-3-Clause",
+	"ISC",
+	"MIT",
+]
 exceptions = [
     { allow = ["MPL-2.0"], name = "option-ext" },
     { allow = ["Unicode-DFS-2016"], name = "unicode-ident" },