And then it started raising errors:

Building in release mode
Compiling .pio\build\esp32dev\src\main.cpp.o
Generating partitions .pio\build\esp32dev\partitions.bin
Compiling .pio\build\esp32dev\libba3\Wire\Wire.cpp.o
Compiling .pio\build\esp32dev\libd16\Tone32\Tone32.cpp.o
Compiling .pio\build\esp32dev\lib5a1\SPI\SPI.cpp.o
In file included from C:\Users\joema.platformio\packages\framework-arduinoespressif32\tools\sdk\include\newlib/pthread.h:33:0,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\xtensa-esp32-elf\bits\gthr-default.h:35,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\xtensa-esp32-elf\bits\gthr.h:148,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\ext\atomicity.h:35,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\bits\basic_string.h:39,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\string:52,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\random:40,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\bits\stl_algo.h:66,
from c:\users\joema.platformio\packages\toolchain-xtensa32\xtensa-esp32-elf\include\c++\5.2.0\algorithm:62,
from C:\Users\joema.platformio\packages\framework-arduinoespressif32\cores\esp32/Arduino.h:142,
from src\main.cpp:1:
lib\Time/time.h:1:2: warning: #warning “Please include TimeLib.h, not Time.h. Future versions will remove Time.h” [-Wcpp]
#warning “Please include TimeLib.h, not Time.h. Future versions will remove Time.h”
^
In file included from src\main.cpp:3:0:
lib\Time/Time.h:1:2: warning: #warning “Please include TimeLib.h, not Time.h. Future versions will remove Time.h” [-Wcpp]
#warning “Please include TimeLib.h, not Time.h. Future versions will remove Time.h”
^
src\main.cpp: In function ‘void loop()’:
src\main.cpp:67:3: error: ‘serial’ was not declared in this scope
serial.begin(9600);
Archiving .pio\build\esp32dev\lib5a1\libSPI.a
^
*** [.pio\build\esp32dev\src\main.cpp.o] Error 1
==================================================================================================== [FAILED] To