README.plugins: Fix version variables

Fixes: #18507

doc/README.plugins

@@ -79,7 +79,7 @@ If you want to add the plugin to your own Windows installer add a text
 file named custom_plugins.txt to the packaging/nsis directory, with a
 "File" statement for NSIS:
 
-File "${STAGING_DIR}\plugins\${VERSION_MAJOR}.${VERSION_MINOR}\epan\foo.dll"
+File "${STAGING_DIR}\plugins\${MAJOR_VERSION}.${MINOR_VERSION}\epan\foo.dll"
 
 3.2 Permanent addition
 
@@ -120,10 +120,10 @@ in the NSIS installer wireshark.nsi file.
 Add the relative path of your plugin DLL (in alphabetical order) to the
 list of "File" statements in the "Dissector Plugins" section:
 
-File "${STAGING_DIR}\plugins\${VERSION_MAJOR}.${VERSION_MINOR}\epan\ethercat.dll"
-File "${STAGING_DIR}\plugins\${VERSION_MAJOR}.${VERSION_MINOR}\epan\foo.dll"
-File "${STAGING_DIR}\plugins\${VERSION_MAJOR}.${VERSION_MINOR}\epan\gryphon.dll"
-File "${STAGING_DIR}\plugins\${VERSION_MAJOR}.${VERSION_MINOR}\epan\irda.dll"
+File "${STAGING_DIR}\plugins\${MAJOR_VERSION}.${MINOR_VERSION}\epan\ethercat.dll"
+File "${STAGING_DIR}\plugins\${MAJOR_VERSION}.${MINOR_VERSION}\epan\foo.dll"
+File "${STAGING_DIR}\plugins\${MAJOR_VERSION}.${MINOR_VERSION}\epan\gryphon.dll"
+File "${STAGING_DIR}\plugins\${MAJOR_VERSION}.${MINOR_VERSION}\epan\irda.dll"
 
 3.2.2.2  Other installers