d/source/lintian-overrides: symlink to overrides for binary package

the files in national encodings also cause a warning for the source
package, which needs its own lintian-overrides file [0].

[0] https://lintian.debian.org/manual/index.html#overrides

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/debian/source/lintian-overrides b/debian/source/lintian-overrides
new file mode 120000 (symlink)
index 0000000..c2ae336
--- /dev/null
+++ b/debian/source/lintian-overrides
@@ -0,0 +1 @@
+../lintian-overrides
\ No newline at end of file