Update downcast-rs requirement from 1.2.1 to 2.0.1

Updates the requirements on [downcast-rs](https://github.com/marcianx/downcast-rs) to permit the latest version.
- [Changelog](https://github.com/marcianx/downcast-rs/blob/master/CHANGELOG.md)
- [Commits](marcianx/downcast-rs@v1.2.1...v2.0.1)

---
updated-dependencies:
- dependency-name: downcast-rs
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Cargo.toml

@@ -38,7 +38,7 @@ levenshtein_automata = "0.2.1"
 uuid = { version = "1.0.0", features = ["v4", "serde"] }
 crossbeam-channel = "0.5.4"
 rust-stemmers = "1.2.0"
-downcast-rs = "1.2.1"
+downcast-rs = "2.0.1"
 bitpacking = { version = "0.9.2", default-features = false, features = [
     "bitpacker4x",
 ] }

columnar/Cargo.toml

@@ -17,7 +17,7 @@ sstable = { version= "0.3", path = "../sstable", package = "tantivy-sstable" }
 common = { version= "0.7", path = "../common", package = "tantivy-common" }
 tantivy-bitpacker = { version= "0.6", path = "../bitpacker/" }
 serde = "1.0.152"
-downcast-rs = "1.2.0"
+downcast-rs = "2.0.1"
 
 [dev-dependencies]
 proptest = "1"