Fix GCC11 C++20 compile error (PR #970)

```
filters.h:1369:49: error: expected ‘)’ before ‘*’ token
    SourceTemplate<T>(BufferedTransformation *attachment)
````

1 files changed, 1 insertions, 1 deletions

diff --git a/filters.h b/filters.h
index 9aa0be93..a334bd76 100644
--- a/filters.h
+++ b/filters.h
@@ -1432,7 +1432,7 @@ public:
 

 	/// \brief Construct a SourceTemplate

 	/// \param attachment an attached transformation

-	SourceTemplate<T>(BufferedTransformation *attachment)

+	SourceTemplate(BufferedTransformation *attachment)

 		: Source(attachment) {}

 	void IsolatedInitialize(const NameValuePairs &parameters)

 		{m_store.IsolatedInitialize(parameters);}