doc: Fix regexp in .known-issues networking.conf file
doc: Fix regexp in .known-issues networking.conf file

This fixes following error:

ERROR: zephyr/.known-issues/doc/networking.conf: bytes 622-1441:
     bad regex: bad escape \I at position 119 (line 2, column 2)
ERROR: E: zephyr/.known-issues/doc/networking.conf: can't load
     config file: bad escape \I at position 119 (line 2, column 2)

Signed-off-by: Jukka Rissanen <f9f077d1da4c7aa947f9864fa5a28c3588f6a45d@linux.intel.com>

GiulianoFranchetto/zephyr,zephyriot/zephyr,nashif/zephyr,punitvara/zephyr,Vudentz/zephyr,Vudentz/zephyr,punitvara/zephyr,kraj/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,explora26/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,aceofall/zephyr-iotos,Vudentz/zephyr,ldts/zephyr,ldts/zephyr,finikorg/zephyr,aceofall/zephyr-iotos,zephyrproject-rtos/zephyr,punitvara/zephyr,Vudentz/zephyr,kraj/zephyr,explora26/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,aceofall/zephyr-iotos,aceofall/zephyr-iotos,aceofall/zephyr-iotos,nashif/zephyr,fbsder/zephyr,punitvara/zephyr,galak/zephyr,fbsder/zephyr,zephyriot/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,zephyriot/zephyr,zephyriot/zephyr,kraj/zephyr,kraj/zephyr,explora26/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,ldts/zephyr,zephyriot/zephyr,ldts/zephyr,ldts/zephyr,finikorg/zephyr,punitvara/zephyr,fbsder/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,fbsder/zephyr,fbsder/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,mbolivar/zephyr