fix: Bump MSRV from 1.91 to 1.92 (#160)

Author: github-actions[bot]

.github/variables/rust-versions.env

@@ -1 +1 @@
-target=1.91
+target=1.92

contract-tests/Cargo.toml

@@ -2,7 +2,7 @@
 name = "contract-tests"
 version = "0.1.0"
 edition = "2021"
-rust-version = "1.91.0"  # MSRV
+rust-version = "1.92.0"  # MSRV
 license = "Apache-2.0"
 
 [dependencies]

launchdarkly-server-sdk/Cargo.toml

@@ -4,7 +4,7 @@ description = "LaunchDarkly Server-Side SDK"
 version = "3.0.0"
 authors = ["LaunchDarkly"]
 edition = "2021"
-rust-version = "1.91.0"  # MSRV
+rust-version = "1.92.0"  # MSRV
 license = "Apache-2.0"
 homepage = "https://docs.launchdarkly.com/sdk/server-side/rust"
 repository = "https://github.com/launchdarkly/rust-server-sdk"