Fallback to lzma-5.2.6

Version 5.2.7 include this commit
https://git.tukaani.org/?p=xz.git;a=commit;h=31d80c6b261b24220776dfaeb8a04f80f80e0a24

With this change, compiling libzim mixed (libzim dynamic and dependencies,
so lzma, statically) fails at libzim linking with a
`src/libzim.so.8.0.1: version node not found for symbol lzma_get_progress@XZ_5.2.2`
error message.

This can be "workaround" by passing `--disable-symbol-versions` to
configure script but then, it is the compilation of kiwix-desktop in
native_dyn which falling with

```
/usr/bin/ld: /usr/lib64/libsystemd.so.0: undefined reference to `lzma_code@XZ_5.0'
/usr/bin/ld: /usr/lib64/libsystemd.so.0: undefined reference to `lzma_end@XZ_5.0'
/usr/bin/ld: /usr/lib64/libsystemd.so.0: undefined reference to `lzma_stream_decoder@XZ_5.0'
/usr/bin/ld: /usr/lib64/libxml2.so.2: undefined reference to `lzma_auto_decoder@XZ_5.0'
/usr/bin/ld: /usr/lib64/libxml2.so.2: undefined reference to `lzma_properties_decode@XZ_5.0'
```

Probably because some native dependencies (Qt ?) use versionned symbols.

This have to be fixed somehow but until then, let's go back to 5.2.6

kiwixbuild/dependencies/lzma.py

@@ -9,9 +9,9 @@ class lzma(Dependency):
     name = 'lzma'
 
     class Source(ReleaseDownload):
-        archive = Remotefile('xz-5.2.7.tar.gz',
-                             '06327c2ddc81e126a6d9a78b0be5014b976a2c0832f492dcfc4755d7facf6d33',
-                             'https://altushost-swe.dl.sourceforge.net/project/lzmautils/xz-5.2.7.tar.gz'
+        archive = Remotefile('xz-5.2.6.tar.gz',
+                             'a2105abee17bcd2ebd15ced31b4f5eda6e17efd6b10f921a01cda4a44c91b3a0',
+                             'https://altushost-swe.dl.sourceforge.net/project/lzmautils/xz-5.2.6.tar.gz'
                             )
 
     class Builder(MakeBuilder):
@@ -24,4 +24,5 @@ class lzma(Dependency):
                     "--disable-lzma-links "
                     "--disable-scripts "
                     "--disable-doc "
-                    "--disable-symbol-versions ")
+#                    "--disable-symbol-versions "
+                  )

kiwixbuild/versions.py

@@ -43,7 +43,7 @@ base_deps_meta_version = '78'
 
 base_deps_versions = {
   'zlib' : '1.2.12',
-  'lzma' : '5.2.7',
+  'lzma' : '5.2.6',
   'zstd' : '1.5.2',
   'docoptcpp' : '0.6.2',
   'uuid' : '1.43.4',