message: Try bumping MSRV to 1.56
diff: @@ -9,7 +9,7 @@ members = [
  name = "async-stripe"
  version = "0.15.0"
  description = "API bindings for the Stripe HTTP API"
  -rust-version = "1.54.0"
  +rust-version = "1.56.0"
  authors = [
  "Anna Baldwin <abaldwin@developers.wyyerd.com>",
  "Kevin Stenerson <kestred@users.noreply.github.com>",
  @@ -22,7 +22,7 @@ repository = "https://github.com/arlyon/async-stripe"
  documentation = "https://docs.rs/async-stripe"
  keywords = ["stripe", "v1", "api", "async"]
  categories = ["api-bindings"]
  -edition = "2018"
  +edition = "2021"
  [package.metadata.docs.rs]
  features = ["runtime-tokio-hyper"]
  @@ -109,14 +109,6 @@ hmac = { version = "0.12", optional = true }
  sha2 = { version = "0.10", optional = true }
  hex = { version = "0.4", optional = true }
  -# pinned deps to prevent msrv breakage
  -indexmap = {version = "1.0,<1.9.0", optional = true}
  -time = {version = "0.3,<0.3.10", optional = true}
  -# >=2.7.0 requires 2021 edition
  -security-framework = {version = "~2.6.0", optional = true}
  -# >=3.11.0 requires 2021 edition
  -bumpalo = {version = "~3.10.0", optional = true}
  -
  [dev-dependencies]
  anyhow = "1.0.38"
  async-std = { version = "1.10.0", features = ["attributes"] }
  