Update the static version check to v0.26
diff --git a/git_static.go b/git_static.go
index d0acb3a..b42d49f 100644
--- a/git_static.go
+++ b/git_static.go
@@ -9,8 +9,8 @@
#cgo !windows pkg-config: --static ${SRCDIR}/vendor/libgit2/build/libgit2.pc
#include <git2.h>
-#if LIBGIT2_VER_MAJOR != 0 || LIBGIT2_VER_MINOR != 25
-# error "Invalid libgit2 version; this git2go supports libgit2 v0.25"
+#if LIBGIT2_VER_MAJOR != 0 || LIBGIT2_VER_MINOR != 26
+# error "Invalid libgit2 version; this git2go supports libgit2 v0.26"
#endif
*/