Fix license headers

I meant to use GPL-3.0-only.

pom.xml

@@ -14,7 +14,7 @@
   <licenses>
     <license>
         <name>GPL-3.0-only</name>
-        <url>https://spdx.org/licenses/GPL-3.0-or-later.html</url>
+        <url>https://spdx.org/licenses/GPL-3.0-only.html</url>
     </license>
   </licenses>
 

src/main/java/io/github/ilri/cgspace/ctasks/CGSpaceCountriesVocabulary.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2020 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.ctasks;

src/main/java/io/github/ilri/cgspace/ctasks/CountriesVocabulary.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2020 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.ctasks;

src/main/java/io/github/ilri/cgspace/ctasks/CountryCodeTagger.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2020 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.ctasks;

src/main/java/io/github/ilri/cgspace/ctasks/ISO3166CountriesVocabulary.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2020 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.ctasks;

src/main/java/io/github/ilri/cgspace/scripts/FixJpgJpgThumbnails.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2020 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.scripts;

src/main/java/io/github/ilri/cgspace/scripts/FixLowQualityThumbnails.java

@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2022 Alan Orth
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: GPL-3.0-only
  */
 
 package io.github.ilri.cgspace.scripts;