Include version.h using a relative path

All the other headers are being included relatively.
19 jobs for master in 6 minutes and 39 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Style
passed #255773
amd64 debian
style-check

00:00:22

 
  Build
passed #255774
amd64 debian
build-debian

00:00:37

passed #255781
debian aarch64
build-debian-aarch64

00:01:24

passed #255782
debian aarch64
build-debian-aarch64-clang-5

00:01:03

passed #255785
debian armv7
build-debian-armv7

00:01:31

passed #255786
debian armv7
build-debian-armv7-clang-5

00:01:01

passed #255775
amd64 debian
build-debian-static

00:00:38

passed #255784
debian aarch64
build-debian-werror

00:00:33

passed #255776
amd64 debian
build-debian32

00:00:28

passed #255783
macos
build-macos

00:00:30

passed #255779
amd64 debian
build-win-arm32

00:00:30

passed #255780
amd64 debian
build-win-arm64

00:00:29

passed #255777
amd64 debian
build-win32

00:00:39

passed #255778
amd64 debian
build-win64

00:00:41

 
  Test
passed #255787
amd64 debian
test-debian

00:00:45

passed #255788
amd64 debian
test-debian-asan

00:02:05

passed #255789
amd64 debian
test-debian-msan

00:01:02

passed #255790
amd64 debian
test-debian-ubsan

00:01:23

passed #255791
amd64 debian
test-win64

00:00:53