[build] Introduce bouncyCastleVersion variable and use it

Also bumps bouncy castle to 1.65.

build.gradle

@@ -116,6 +116,7 @@ allprojects {
 		].collect { project(it) }
 		junitVersion = '5.6.0'
 		commonsIoVersion = '2.6'
+		bouncyCastleVersion = '1.65'
 		if (project.hasProperty("useSonatype")) {
 			useSonatype = project.getProperty("useSonatype").toBoolean()
 		} else {

smack-core/build.gradle

@@ -18,7 +18,7 @@ dependencies {
 	// 'implementation' here since there is no need to shadow it
 	// outside of the fixtures compilation classpath. That is, no test
 	// should ever setup Bouncy Castle as security provider explicitly.
-	testFixturesImplementation 'org.bouncycastle:bcprov-jdk15on:1.64'
+	testFixturesImplementation "org.bouncycastle:bcprov-jdk15on:${bouncyCastleVersion}"
 	testFixturesImplementation 'org.apache.commons:commons-lang3:3.10'
 
 	testFixturesApi "org.jxmpp:jxmpp-jid:$jxmppVersion:tests"

smack-openpgp/build.gradle

@@ -10,7 +10,7 @@ dependencies {
 
 	api 'org.pgpainless:pgpainless-core:0.0.1-alpha11'
 
-	testImplementation "org.bouncycastle:bcprov-jdk15on:1.65"
+	testImplementation "org.bouncycastle:bcprov-jdk15on:${bouncyCastleVersion}"
 
 	testFixturesApi(testFixtures(project(":smack-core")))
 	testCompile group: 'commons-io', name: 'commons-io', version: "$commonsIoVersion"