create changelog (#1917)

* add changelog

* clarify

* add october release

* mention tle

* add how-to

firmware/CHANGELOG.md

@@ -0,0 +1,49 @@
+<!---
+
+How to use this file:
+- When making a change to the firmware that users should know about, add it to the
+	appropriate section (breaking/added/fixed) in the next release.
+- If it's something interesting or breaking, make a post about it on the forum! We want users
+	to find out about changes before they have to get help because their car won't start.
+
+Release template (copy/paste this for new release):
+
+## Month 202x Release - "Release Name"
+
+### Breaking Changes
+ -   
+
+### Added
+ -   
+
+### Fixed
+ -   
+
+ -->
+
+# Changelog
+
+All notable user-facing or behavior-altering changes will be documented in this file.
+
+## November 2020 Release
+
+### Breaking Changes
+ -   "AFR target" table is now "Lambda target" table.  It should convert itself correctly, but a backup of that table is recommended when updating firmware/ini.
+ -   "Base cranking fuel" is now in milligrams, using the full injector model at all times now.  60mg per liter per cylinder is a good starting point
+
+### Added
+ -   High & low pressure fuel sensor channels
+ -   Electronic throttle-style wastegate control found on some VW turbos (and VGTs)
+ -   Improved TLE8888 driver on microRusEfi 
+
+## October 2020 Release - "Sausage Pizza Day"
+
+### Added
+ -   `iat` as FSIO variable to read intake air temperature
+ -   [ALPHA] Software based knock detection on Proteus v0.4+.  Possible on microRusEfi and Frankenso too with hardware modification.
+ -   [ALPHA] Early framing work for automatic transmission control!
+
+### Fixed
+ -   Fixed fuel pump logic
+ -   Improve trigger input/decode and PWM performance
+ -   Fixes to SD card logging