corrected address for gvm-libs asc

Related to issue #564

Author: ioannisp7

src/22.4/source-build/gvm-libs/download.md

@@ -2,7 +2,7 @@
 :caption: Downloading the gvm-libs sources
 
 curl -f -L https://github.com/greenbone/gvm-libs/archive/refs/tags/v$GVM_LIBS_VERSION.tar.gz -o $SOURCE_DIR/gvm-libs-$GVM_LIBS_VERSION.tar.gz
-curl -f -L https://github.com/greenbone/gvm-libs/releases/download/v$GVM_LIBS_VERSION/gvm-libs-v$GVM_LIBS_VERSION.tar.gz.asc -o $SOURCE_DIR/gvm-libs-$GVM_LIBS_VERSION.tar.gz.asc
+curl -f -L https://github.com/greenbone/gvm-libs/releases/download/v$GVM_LIBS_VERSION/gvm-libs-$GVM_LIBS_VERSION.tar.gz.asc -o $SOURCE_DIR/gvm-libs-$GVM_LIBS_VERSION.tar.gz.asc
 ```
 
 ```{code-block}