Fix broken version of rle-decode-fast

Cargo.toml

@@ -50,6 +50,11 @@ libflate = "2"
 maplit = "1.0.1"
 pretty_assertions = "1"
 rand = { version = "0.8", features = ["small_rng"] }
+serde = { version = "1.0.145" }
+testing_logger = "0.1.1"
+
+# for -Zminimal-versions
+[target.'cfg(any())'.dependencies]
 # Force criterion to pull in regex 1.6 instead of 1.5 during minimal version CI;
 # otherwise compilation fails with...
 # ```
@@ -61,14 +66,9 @@ rand = { version = "0.8", features = ["small_rng"] }
 # ```
 # Forcing >= 1.5.1 would be enough to solve this issue, but since regex 1.6.0
 # supports our minimum supported rust version of 1.59.0, regex 1.6.x is fine
-regex = { version = "1.6", default-features = false, features = ["std"] }
-# Force criterion to pull in serde 1.0.145 instead of 1.0.0 during minimal version CI;
-# otherwise compilation fails with many errors (since serde 1.0.0 is such an old
-# crate). There is likely a lower version of serde than 1.0.145 that would also
-# successfully compile in minimal version CI, but since serde 1.0.145 is supported
-# by our minimum supported rust version of 1.59.0, being on >= 1.0.145 is fine
-serde = { version = "1.0.145" }
-testing_logger = "0.1.1"
+regex = { version = "1.6", default-features = false, optional = true }
+# rle-decode-fast 1.0.0 no longer builds with newer Rust
+rle-decode-fast = { version = "1.0.3", default-features = false, optional = true }
 
 [lib]
 name = "inferno"