Prefix ENV var name with DEPENDABOT_

Might be a bit overly cautious, but this should prevent collisions in
the event that another value is set somewhere.

src/updater-builder.ts

@@ -42,6 +42,7 @@ export class UpdaterBuilder {
         `DEPENDABOT_JOB_ID=${this.jobParams.jobId}`,
         `DEPENDABOT_JOB_TOKEN=${this.jobParams.jobToken}`,
         `DEPENDABOT_JOB_PATH=${JOB_INPUT_PATH}/${JOB_INPUT_FILENAME}`,
+        `DEPENDABOT_OPEN_TIMEOUT_IN_SECONDS=10`,
         `DEPENDABOT_OUTPUT_PATH=${JOB_OUTPUT_PATH}/${JOB_OUTPUT_FILENAME}`,
         `DEPENDABOT_REPO_CONTENTS_PATH=${REPO_CONTENTS_PATH}`,
         `DEPENDABOT_API_URL=${this.jobParams.dependabotApiDockerUrl}`,
@@ -50,8 +51,7 @@ export class UpdaterBuilder {
         `HTTP_PROXY=${this.proxy.url}`,
         `https_proxy=${this.proxy.url}`,
         `HTTPS_PROXY=${this.proxy.url}`,
-        `ENABLE_CONNECTIVITY_CHECK=1`,
-        `OPEN_TIMEOUT_IN_SECONDS=10`
+        `ENABLE_CONNECTIVITY_CHECK=1`
       ],
       Cmd: ['sh', '-c', cmd],
       HostConfig: {