feat: add temperature unit conversions (#5315)

Co-authored-by: Bama Charan Chhandogi <b.c.chhandogi@gmail.com>

src/test/java/com/thealgorithms/conversions/UnitsConverterTest.java

@@ -0,0 +1,18 @@
+package com.thealgorithms.conversions;
+
+import static java.util.Map.entry;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.Map;
+import org.apache.commons.lang3.tuple.Pair;
+import org.junit.jupiter.api.Test;
+
+public class UnitsConverterTest {
+
+    @Test
+    void testConvertThrowsForSameUnits() {
+        final UnitsConverter someConverter = new UnitsConverter(Map.ofEntries(entry(Pair.of("A", "B"), new AffineConverter(10.0, -20.0))));
+        assertThrows(IllegalArgumentException.class, () -> someConverter.convert("A", "A", 20.0));
+        assertThrows(IllegalArgumentException.class, () -> someConverter.convert("B", "B", 20.0));
+    }
+}