doc: release-notes: announce nvs_init deprecation

Add a note about deprecation of nvs_init in favor of nvs_mount.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

doc/releases/release-notes-3.1.rst

@@ -0,0 +1,173 @@
+:orphan:
+
+.. _zephyr_3.1:
+
+Zephyr 3.1.0 (Working Draft)
+############################
+
+The following sections provide detailed lists of changes by component.
+
+Security Vulnerability Related
+******************************
+
+Known issues
+************
+
+API Changes
+***********
+
+Changes in this release
+=======================
+
+Removed APIs in this release
+============================
+
+Deprecated in this release
+==========================
+
+* :c:func:`nvs_init` is deprecated in favor of utilizing :c:func:`nvs_mount`.
+
+Stable API changes in this release
+==================================
+
+New APIs in this release
+========================
+
+Kernel
+******
+
+Architectures
+*************
+
+* ARM
+
+  * AARCH32
+
+  * AARCH64
+
+* Xtensa
+
+Bluetooth
+*********
+
+* Audio
+
+* Direction Finding
+
+* Host
+
+* Mesh
+
+* Controller
+
+* HCI Driver
+
+Boards & SoC Support
+********************
+
+* Added support for these SoC series:
+
+* Removed support for these SoC series:
+
+* Made these changes in other SoC series:
+
+* Changes for ARC boards:
+
+* Added support for these ARM boards:
+
+* Added support for these ARM64 boards:
+
+* Removed support for these ARM boards:
+
+* Removed support for these X86 boards:
+
+* Added support for these RISC-V boards:
+
+* Made these changes in other boards:
+
+* Added support for these following shields:
+
+
+Drivers and Sensors
+*******************
+
+* ADC
+
+* CAN
+
+* Counter
+
+* DAC
+
+* Disk
+
+* DMA
+
+* EEPROM
+
+* Entropy
+
+* Ethernet
+
+* Flash
+
+* GPIO
+
+* I2C
+
+* I2S
+
+* Interrupt Controller
+
+* MBOX
+
+* MEMC
+
+* Pin control
+
+* PWM
+
+* Sensor
+
+* Serial
+
+* SPI
+
+* Timer
+
+* USB
+
+* Watchdog
+
+Networking
+**********
+
+USB
+***
+
+Build and Infrastructure
+************************
+
+Libraries / Subsystems
+**********************
+
+HALs
+****
+
+MCUboot
+*******
+
+Trusted Firmware-m
+******************
+
+Documentation
+*************
+
+Tests and Samples
+*****************
+
+Issue Related Items
+*******************
+
+These GitHub issues were addressed since the previous 3.0.0 tagged
+release: