chore(deps): update otel/weaver docker tag to v0.21.0 (#408)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

build.gradle.kts

@@ -120,7 +120,7 @@ fun generateTask(taskName: String, incubating: Boolean) {
         "--mount", "type=bind,source=${modelPath},target=/home/weaver/source,readonly",
         "--mount", "type=bind,source=$projectDir/buildscripts/templates,target=/home/weaver/templates,readonly",
         "--mount", "type=bind,source=$projectDir/$outputDir,target=/home/weaver/target",
-        "otel/weaver:v0.20.0@sha256:fa4f1c6954ecea78ab1a4e865bd6f5b4aaba80c1896f9f4a11e2c361d04e197e",
+        "otel/weaver:v0.21.0@sha256:b144c94bbb8b09246f24d2b705636e177af8fd954f9f6756e7fb5663d6f86188",
         "registry", "generate",
         "--registry=/home/weaver/source",
         "--templates=/home/weaver/templates",