message: Make indexmap required dep
diff: @@ -30,7 +30,7 @@ debug = true
  [dependencies]
  fixedbitset = { version = "0.2.0", default-features = false }
  quickcheck = { optional = true, version = "0.8", default-features = false }
  -indexmap = { version = "1.0.2", optional = true }
  +indexmap = { version = "1.0.2" }
  serde = { version = "1.0", optional = true }
  serde_derive = { version = "1.0", optional = true }
  @@ -42,7 +42,7 @@ itertools = { version = "0.8", default-features = false }
  [features]
  default = ["graphmap", "stable_graph", "matrix_graph"]
  -graphmap = ["indexmap"]
  +graphmap = []
  serde-1 = ["serde", "serde_derive"]
  stable_graph = []
  matrix_graph = []
  