lower msrv to 1.43

.github/workflows/rust.yml

@@ -31,3 +31,18 @@ jobs:
       - uses: actions-rs/cargo@v1
         with:
           command: test
+
+  msrv:
+    name: Check MSRV
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: 1.43
+          override: true
+      - uses: Swatinem/rust-cache@v1
+      - uses: actions-rs/cargo@v1
+        with:
+          command: check

src/lib.rs

@@ -510,7 +510,7 @@ impl<'de> Visitor<'de> for ValueVisitor {
     where
         E: de::Error,
     {
-        Ok(Value::String(v.into()))
+        Ok(Value::String(v.to_string()))
     }
 
     fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
@@ -668,7 +668,7 @@ impl<'de> Visitor<'de> for KeyVisitor {
     where
         E: de::Error,
     {
-        Ok(Key::String(v.into()))
+        Ok(Key::String(v.to_string()))
     }
 
     fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>