add fan curve support, parity with Linux daemon

fan curves and model strings current as-of:
  https://github.com/pop-os/system76-power/blob/79b02d/src/fan.rs

also add note about rust 1.53 or newer to README.md and bump ./rust-toolchain to 1.55 (latest release)

This is due to the use of "or patterns" inside a match. This was
stabilized in rust 1.53: rust-lang/rust#79278

(and, I believe, is being used in the Linux daemon)

README.md

@@ -1,7 +1,7 @@
 # Thelio Io Windows Driver (WORK IN PROGRESS)
 
 - Install GIT LFS prior to cloning this repository
-- Install Rust from https://rustup.rs/
+- Install Rust from https://rustup.rs/ 1.53.0 or newer (ie `rustup toolchain install 1.55.0`)
 - Install Chocolaty from https://chocolatey.org/install
 - Launch an Administrator Command Prompt and run the following:
 ```

rust-toolchain

@@ -1 +1 @@
-1.50.0
+1.55.0

src/main.rs

@@ -90,6 +90,19 @@ fn driver() -> io::Result<()> {
             debug!("{} {} uses standard fan curve", sys_vendor, product_version);
             FanCurve::standard()
         },
+        ("System76", "thelio-major-r1") => {
+            debug!("{} {} uses threadripper2 fan curve", sys_vendor, product_version);
+            FanCurve::threadripper2()
+        },
+        ("System76", "thelio-major-r2" | "thelio-major-r2.1" | "thelio-major-b1" | "thelio-major-b2"
+                   | "thelio-major-b3" | "thelio-mega-r1" | "thelio-mega-r1.1" ) => {
+            debug!("{} {} uses hedt fan curve", sys_vendor, product_version);
+            FanCurve::hedt()
+        },
+        ("System76", "thelio-massive-b1") => {
+            debug!("{} {} uses xeon fan curve", sys_vendor, product_version);
+            FanCurve::xeon()
+        },
         _ => return Err(io::Error::new(
             io::ErrorKind::Other,
             format!(