Updated to 0.15.2

[georg95]

Added 0.15.2 version(latest release)

https://georg95.github.io/zig.guide/
Changed paths, now 0.15 is on root /, also search is in 0.15
Removed warnings about unstable versions
Changed ArrayList allocator to fixed size arrays to store paths, due to changed allocator APIs in 0.15

Fixed broken json example (second)

https://zig.guide/master/standard-library/json
->
https://georg95.github.io/zig.guide/standard-library/json

Fixed broken custom writer example (last)

std.io.Writer -> std.io.GenericWriter
https://zig.guide/master/standard-library/readers-and-writers
->
https://georg95.github.io/zig.guide/standard-library/readers-and-writers

Updated 0.14 to 0.14.1:

Fixed broken json example (second)

https://zig.guide/master/standard-library/json
->
https://georg95.github.io/zig.guide/0.14/standard-library/json

[charlesgardyn]

Nice. I can also help to maintain this website.

[Sobeston]

Hi, apologies for not getting around to merging this. Unfortunately due to the project's structure this PR was more difficult to review than doing it myself. Going to try and make the release process easier.