docs: update software request guidance in README

[adrianreber]

Encourage contributors to open issues or pull requests instead of pointing to the old submission page.

[github-actions]

🚀 CCache Statistics

Configuration	🐧 RHEL	🦊 openEuler
🖥️ x86_64 / gnu15	🟡 43.42%	🔴 11.28%
🖥️ x86_64 / intel	🔴 4.19%	-
💪 aarch64 / gnu15	🟡 43.42%	🔴 12.98%

📊 Detailed Statistics

openEuler (aarch64)

Cacheable calls:    6747 / 8400 (80.32%)
  Hits:              876 / 6747 (12.98%)
    Direct:          547 /  876 (62.44%)
    Preprocessed:    329 /  876 (37.56%)
  Misses:           5871 / 6747 (87.02%)
Uncacheable calls:  1653 / 8400 (19.68%)
Local storage:
  Cache size (GiB):  0.4 /  5.0 ( 7.85%)
  Hits:              876 / 6747 (12.98%)
  Misses:           5871 / 6747 (87.02%)

openEuler (x86_64)

Cacheable calls:    10776 / 12590 (85.59%)
  Hits:              1215 / 10776 (11.28%)
    Direct:           859 /  1215 (70.70%)
    Preprocessed:     356 /  1215 (29.30%)
  Misses:            9561 / 10776 (88.72%)
Uncacheable calls:   1814 / 12590 (14.41%)
Local storage:
  Cache size (GiB):   0.6 /   5.0 (11.81%)
  Hits:              1215 / 10776 (11.28%)
  Misses:            9561 / 10776 (88.72%)

RHEL (aarch64/gnu15)

Cacheable calls:     76 / 168 (45.24%)
  Hits:              33 /  76 (43.42%)
    Direct:          33 /  33 (100.0%)
    Preprocessed:     0 /  33 ( 0.00%)
  Misses:            43 /  76 (56.58%)
Uncacheable calls:   92 / 168 (54.76%)
Local storage:
  Cache size (GiB): 0.0 / 5.0 ( 0.02%)
  Hits:              33 /  76 (43.42%)
  Misses:            43 /  76 (56.58%)

RHEL (x86_64/gnu15)

Cacheable calls:     76 / 168 (45.24%)
  Hits:              33 /  76 (43.42%)
    Direct:          33 /  33 (100.0%)
    Preprocessed:     0 /  33 ( 0.00%)
  Misses:            43 /  76 (56.58%)
Uncacheable calls:   92 / 168 (54.76%)
Local storage:
  Cache size (GiB): 0.0 / 5.0 ( 0.02%)
  Hits:              33 /  76 (43.42%)
  Misses:            43 /  76 (56.58%)

RHEL (x86_64/intel)

Cacheable calls:    2962 / 4646 (63.75%)
  Hits:              124 / 2962 ( 4.19%)
    Direct:           89 /  124 (71.77%)
    Preprocessed:     35 /  124 (28.23%)
  Misses:           2838 / 2962 (95.81%)
Uncacheable calls:  1684 / 4646 (36.25%)
Local storage:
  Cache size (GiB):  0.0 /  5.0 ( 0.70%)
  Hits:              124 / 2962 ( 4.19%)
  Misses:           2838 / 2962 (95.81%)

---

🤖 Generated from workflow run 24421787216

[github-actions]

Test Results

 29 files  ±0  29 suites  ±0   45s ⏱️ -1s
 59 tests ±0  53 ✅ ±0  6 💤 ±0  0 ❌ ±0 
105 runs  ±0  97 ✅ ±0  8 💤 ±0  0 ❌ ±0 

Results for commit 665ebf9. ± Comparison against base commit a3f598b.