#32 adds libsodium 26 to supported versions

Arch already has said version and it runs the test-suite just fine.
So no major breaking changes.

Author: PhilippMDoerner

libsodium/sodium.nim

@@ -17,7 +17,7 @@ when defined(windows):
 elif defined(macosx):
   const libsodium_fn* = "libsodium.dylib"
 else:
-  const libsodium_fn* = "libsodium.so(.18|.23)"
+  const libsodium_fn* = "libsodium.so(.18|.23|.26)"
 
 
 {.pragma: sodium_import, importc, dynlib: libsodium_fn.}

libsodium/sodium_sizes.nim

@@ -10,7 +10,7 @@ when defined(windows):
 elif defined(macosx):
   const libsodium_fn* = "libsodium.dylib"
 else:
-  const libsodium_fn* = "libsodium.so(.18|.23)"
+  const libsodium_fn* = "libsodium.so(.18|.23|.26)"
 
 {.pragma: sodium_import, importc, dynlib: libsodium_fn.}