Disable default-features for dependency prometheus

By default, the prometheus crate enables the feature to push metrics, which is not used in this libary.
If needed, a downstream user can enable the feature flag.

Cargo.toml

@@ -3,7 +3,7 @@ members = [
     "foundations",
     "foundations-macros",
     "examples",
-    "tools/gen-syscall-enum"
+    "tools/gen-syscall-enum",
 ]
 resolver = "2"
 
@@ -41,7 +41,7 @@ ipnetwork = "0.20"
 once_cell = "1.5"
 parking_lot = "0.12"
 proc-macro2 = { version = "1", default-features = false }
-prometheus = "0.13.3"
+prometheus = { version = "0.13.3", default-features = false }
 prometheus-client = "0.18.1"
 prometools = "0.2.1"
 rand = "0.8"