build: also check for capital X when verifying contributing guidelines acknowledgment

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---

---
type: pre_push_report
description: Results of running various checks prior to pushing changes.
report:
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    status: na
  - task: run_c_examples
    status: na
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    status: na
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    status: na
---

---
type: pre_push_report
description: Results of running various checks prior to pushing changes.
report:
  - task: run_javascript_examples
    status: na
  - task: run_c_examples
    status: na
  - task: run_cpp_examples
    status: na
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    status: na
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    status: na
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    status: na
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    status: na
  - task: run_javascript_benchmarks
    status: na
  - task: run_julia_benchmarks
    status: na
  - task: run_python_benchmarks
    status: na
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  - task: run_javascript_tests
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---

Author: Planeshifter

.github/workflows/scripts/check_contributing_guidelines_acceptance

@@ -72,7 +72,7 @@ main() {
 	fi
 
 	# Check for the contributing guidelines checkbox:
-	if echo "${pr_body}" | grep -qE '^\s*-\s*\[x\]\s*Read,\s*understood,\s*and\s*followed\s*the\s*\[contributing\s*guidelines\]'; then
+	if echo "${pr_body}" | grep -qE '^\s*-\s*\[[xX]\]\s*Read,\s*understood,\s*and\s*followed\s*the\s*\[contributing\s*guidelines\]'; then
 		echo "Contributing guidelines acknowledged."
 		print_success
 		exit 0