style: fix eslint warnings

Author: microshine

src/certs/csr.ts

@@ -108,7 +108,7 @@ export class X509CertificateRequest extends CryptoCertificate implements core.Cr
   protected parse(data: ArrayBuffer): void {
     try {
       this.csr = new x509.Pkcs10CertificateRequest(data);
-    } catch (e) {
+    } catch {
       throw new ParserError("Cannot parse PKCS10 certificate request");
     }
   }

src/certs/x509.ts

@@ -128,7 +128,7 @@ export class X509Certificate extends CryptoCertificate implements core.CryptoX50
   protected parse(data: ArrayBuffer): void {
     try {
       this.x509 = new x509.X509Certificate(data);
-    } catch (e) {
+    } catch {
       throw new ParserError("Cannot parse X509 certificate");
     }
   }

src/key.ts

@@ -120,7 +120,7 @@ export class CryptoKey<T extends Pkcs11KeyAlgorithm = Pkcs11KeyAlgorithm> extend
     try {
       // Yubico throws CKR_ATTRIBUTE_TYPE_INVALID
       this.extractable = key.extractable;
-    } catch (e) {
+    } catch {
       this.extractable = false;
     }
     this.usages = [];
@@ -160,7 +160,7 @@ export class CryptoKey<T extends Pkcs11KeyAlgorithm = Pkcs11KeyAlgorithm> extend
     try {
       // Yubico throws CKR_ATTRIBUTE_TYPE_INVALID
       this.extractable = key.extractable;
-    } catch (e) {
+    } catch {
       this.extractable = false;
     }
     if (key.sign) {