fix: Bump MSRV to 1.60.0

This is over 6 months old and allows us to hide optional dependencies as
features so we can change them without breaking compatibility (after the
first time).

.clippy.toml

@@ -0,0 +1 @@
+msrv = "1.60.0"  # MSRV

.github/workflows/ci.yml

@@ -55,15 +55,15 @@ jobs:
     - name: Run crate example
       run: cargo run --example default
   msrv:
-    name: "Check MSRV: 1.41.0"
+    name: "Check MSRV: 1.60.0"
     runs-on: ubuntu-latest
     steps:
     - name: Checkout repository
       uses: actions/checkout@v3
     - name: Install Rust
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: 1.41.0  # MSRV
+        toolchain: 1.60.0  # MSRV
         profile: minimal
         override: true
     - uses: Swatinem/rust-cache@v1
@@ -119,7 +119,7 @@ jobs:
     - name: Install Rust
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: 1.41.0  # MSRV
+        toolchain: 1.60.0  # MSRV
         profile: minimal
         override: true
         components: clippy

Cargo.toml

@@ -14,8 +14,8 @@ license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-cli/env_logger/"
 categories = ["development-tools::debugging"]
 keywords = ["logging", "log", "logger"]
-edition = "2018"
-rust-version = "1.41.0"  # MSRV
+edition = "2021"
+rust-version = "1.60.0"  # MSRV
 include = [
   "build.rs",
   "src/**/*",