update min Rust version to 1.42.0

rusqlite 0.24.1 uses matches!, which was introduced in this version.
So 1682553 does't work on prior versions.

https://travis-ci.org/github/scottlamb/moonfire-nvr/jobs/745309747

.travis.yml

@@ -23,7 +23,7 @@ matrix:
       script:
         - ci/script-rust.sh
     - language: rust
-      rust: 1.40.0
+      rust: 1.42.0
       script:
         - ci/script-rust.sh
     - language: node_js

guide/install-manual.md

@@ -48,7 +48,7 @@ $ sudo apt-get install \
                tzdata
 ```
 
-Next, you need Rust 1.40+ and Cargo. The easiest way to install them is by
+Next, you need Rust 1.42+ and Cargo. The easiest way to install them is by
 following the instructions at [rustup.rs](https://www.rustup.rs/).
 
 Finally, building the UI requires [yarn](https://yarnpkg.com/en/).

scripts/script-functions.sh

@@ -40,7 +40,7 @@ fi
 NODE_MIN_VERSION="10"
 YARN_MIN_VERSION="1.0"
 CARGO_MIN_VERSION="0.2"
-RUSTC_MIN_VERSION="1.40"
+RUSTC_MIN_VERSION="1.42"
 
 normalizeDirPath()
 {