Fix updateCopyright Gradle task to read files in UTF-8

This would avoid non-ASCII symbols breakage on those operating systems where UTF-8 is not default

build.gradle

@@ -181,7 +181,7 @@ configure(javaProjects) { subproject ->
 							def beginningYear = matcher[0][1]
 							if (now != beginningYear && now != matcher[0][2]) {
 								def years = "$beginningYear-$now"
-								def sourceCode = file.text
+								def sourceCode = file.getText('UTF-8')
 								sourceCode = sourceCode.replaceFirst(/20\d\d(-20\d\d)?/, years)
 								file.text = sourceCode
 								println "Copyright updated for file: $file"