Avoid rising "unicode exception" when running from mp1.24

Peripheral register definitions were moved to a new directory
inside the ESP-IDF: components/soc/{cpu_type}/register.

This change caused our compat tests to fail because they
depended on predefined register constants.

This commit resolves the issue by adding the new directory to
GCC's include search path using the -I option.

Additionally, all header files in this new directory are now
added to the DefinesDB for the compat tests with RTC macros.

Fixes micropython#100.

…ludes

Fix compat tests due to esp-idf moving include files

Open ulp file in binary mode instead of text mode

An example that uses ULP self-modifying code to create a PWM-like LED dimming effect on GPIO 15.

Example code for reading the temperature of the chip using the ULP of the ESP32-S2

GitHub has deprecated and removed the ubuntu-20.04 builder image.
This commit updates the build process to use the ubuntu-22.04
image instead.

Update builder image to ubuntu-22.04

made the default LED pin 4, with the option for the user to change led_pin.

MicroPython 1.25.0 introduced a breaking change, aligning the behaviour
of the int() function with the behaviour of CPython (assume a decimal
number, unless a base is specified. Only if a base of 0 is specified
will the base be inferred from the string).

This commit implements a new custom parsing function `parse_int`. It
can correctly parse the following string literals:

* 0x[0-9]+ -> treated as hex
* 0b[0-9]+ -> treated as binary
* 0o[0-9]+ -> treated as octal (Python style)
* 0[0-9]+ -> treated as octal (GNU as style)
* anything else parsed as decimal

It only handles the GNU as style octal case directly, letting the
original `int()` function handle the other cases (using base 0).

In fact, the GNU as octal case was not handled correctly previously,
and this commit fixes that.

Some new tests for previous functionality were added to show that
both new and previous cases are being handled correctly.

Note: GNU as does not actually accept the octal prefix 0o..., but we
accept it as a convenience, as this is accepted in Python code. This
means however, that our assembler accepts code which GNU as does not
accept. But the other way around, we still accept all code that GNU
as accepts, which was one of our goals.

…h-base-prefix

Fix parsing of integer literals with base prefix

Add LED Fade and Temperature sensing example