fix: upgrade ci jobs to jdk 21 (#926)

Signed-off-by: Sam Gammon <sam@elide.dev>

.circleci/jobs/BuildNativeJob.pkl

@@ -24,7 +24,7 @@ arch: "amd64"|"aarch64"
 /// Whether to link to musl. Otherwise, links to glibc.
 musl: Boolean = false
 
-javaVersion = "17.0"
+javaVersion = "21.0"
 
 local setupLinuxEnvironment: Config.RunStep =
   let (muslVersion = "1.2.2")

.circleci/jobs/DeployJob.pkl

@@ -19,7 +19,7 @@ import "package://pkg.pkl-lang.org/pkl-pantry/com.circleci.v2@1.1.2#/Config.pkl"
 
 local self = this
 
-javaVersion = "17.0"
+javaVersion = "21.0"
 
 command: String
 

.circleci/jobs/SimpleGradleJob.pkl

@@ -23,7 +23,7 @@ command: String
 
 os = "linux"
 
-javaVersion = "17.0"
+javaVersion = "21.0"
 
 steps {
   new Config.RunStep {