turn off decimal dependency default features (#33)

* turn off decimal dependency default features

to get rid of https://rustsec.org/advisories/RUSTSEC-2022-0004

* disable default features, but still enable serde and ord_subset

just dropping rustc-serialize as per @probablykasper

Cargo.lock

@@ -42,7 +42,6 @@ dependencies = [
  "cc",
  "libc",
  "ord_subset",
- "rustc-serialize",
  "serde",
 ]
 
@@ -81,12 +80,6 @@ version = "0.6.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
 
-[[package]]
-name = "rustc-serialize"
-version = "0.3.24"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
-
 [[package]]
 name = "serde"
 version = "1.0.159"

Cargo.toml

@@ -10,10 +10,19 @@ homepage = "https://github.com/probablykasper/cpc#readme"
 repository = "https://github.com/probablykasper/cpc"
 documentation = "https://docs.rs/cpc"
 keywords = ["math", "expression", "evaluate", "units", "convert"]
-categories = ["mathematics", "science", "parsing", "text-processing", "value-formatting"]
+categories = [
+    "mathematics",
+    "science",
+    "parsing",
+    "text-processing",
+    "value-formatting",
+]
 
 [dependencies]
-decimal = "2.1"
+decimal = { version = "2.1", default-features = false, features = [
+    "serde",
+    "ord_subset",
+] }
 unicode-segmentation = "1.10"
 
 [dev-dependencies]