Fix min/max private variables overflow

[bleubidon]

Using an int8_t for min and max causes the computation of this->min and this->max in Servo::attach(int pin, int min, int max) to overflow (for instance when calling my_servo.attach(my_pin, 544, 1100), following https://www.arduino.cc/reference/en/libraries/servo/attach/).

[CLAassistant]

All committers have signed the CLA.

[github-actions]

Memory usage change @ 7b4f264

Board	flash	%	RAM for global variables	%
arduino:avr:leonardo	🔺 +8 - +8	+0.03 - +0.03	🔺 +2 - +2	+0.08 - +0.08
arduino:avr:mega	🔺 +8 - +8	0.0 - 0.0	🔺 +2 - +2	+0.02 - +0.02
arduino:avr:nano	🔺 +8 - +8	+0.03 - +0.03	🔺 +2 - +2	+0.1 - +0.1
arduino:mbed_nano:nano33ble	💚 -64 - 0	-0.01 - 0.0	🔺 +8 - +8	0.0 - 0.0
arduino:mbed_nano:nanorp2040connect	💚 -4 - -4	-0.0 - -0.0	🔺 +8 - +8	0.0 - 0.0
arduino:mbed_portenta:envie_m4	0 - 0	0.0 - 0.0	🔺 +8 - +8	0.0 - 0.0
arduino:mbed_portenta:envie_m7	0 - 0	0.0 - 0.0	🔺 +8 - +8	0.0 - 0.0
arduino:megaavr:nona4809	🔺 +8 - +8	+0.02 - +0.02	🔺 +2 - +2	+0.03 - +0.03
arduino:sam:arduino_due_x_dbg	💚 -16 - -8	-0.0 - -0.0	N/A	N/A
arduino:samd:mkrzero	💚 -8 - -8	-0.0 - -0.0	🔺 +8 - +8	+0.02 - +0.02

Click for full report table

Board	examples/Knob flash	%	examples/Knob RAM for global variables	%	examples/Sweep flash	%	examples/Sweep RAM for global variables	%
arduino:avr:leonardo	8	0.03	2	0.08	8	0.03	2	0.08
arduino:avr:mega	8	0.0	2	0.02	8	0.0	2	0.02
arduino:avr:nano	8	0.03	2	0.1	8	0.03	2	0.1
arduino:mbed_nano:nano33ble	0	0.0	8	0.0	-64	-0.01	8	0.0
arduino:mbed_nano:nanorp2040connect	-4	-0.0	8	0.0	-4	-0.0	8	0.0
arduino:mbed_portenta:envie_m4	0	0.0	8	0.0	0	0.0	8	0.0
arduino:mbed_portenta:envie_m7	0	0.0	8	0.0	0	0.0	8	0.0
arduino:megaavr:nona4809	8	0.02	2	0.03	8	0.02	2	0.03
arduino:sam:arduino_due_x_dbg	-16	-0.0	N/A	N/A	-8	-0.0	N/A	N/A
arduino:samd:mkrzero	-8	-0.0	8	0.02	-8	-0.0	8	0.02

Click for full report CSV

Board,examples/Knob<br>flash,%,examples/Knob<br>RAM for global variables,%,examples/Sweep<br>flash,%,examples/Sweep<br>RAM for global variables,%
arduino:avr:leonardo,8,0.03,2,0.08,8,0.03,2,0.08
arduino:avr:mega,8,0.0,2,0.02,8,0.0,2,0.02
arduino:avr:nano,8,0.03,2,0.1,8,0.03,2,0.1
arduino:mbed_nano:nano33ble,0,0.0,8,0.0,-64,-0.01,8,0.0
arduino:mbed_nano:nanorp2040connect,-4,-0.0,8,0.0,-4,-0.0,8,0.0
arduino:mbed_portenta:envie_m4,0,0.0,8,0.0,0,0.0,8,0.0
arduino:mbed_portenta:envie_m7,0,0.0,8,0.0,0,0.0,8,0.0
arduino:megaavr:nona4809,8,0.02,2,0.03,8,0.02,2,0.03
arduino:sam:arduino_due_x_dbg,-16,-0.0,N/A,N/A,-8,-0.0,N/A,N/A
arduino:samd:mkrzero,-8,-0.0,8,0.02,-8,-0.0,8,0.02